perlite institute technical q&a’s june 2018 – august 2018
TRANSCRIPT
Perlite Institute Technical Q&A’s June 2018 – August
2018Perlite Institute Technical Q&A’s June 2018 – August
2018
Q1: We buy truckloads of perlite for pre-coating baghouse filters. It always works and does a good
job. A few days ago, I got a call from an end user who noticed that the color of the perlite was slightly
darker that what he always gets. His suspicion led him to believe that there were magnetic particles in
the product which is a no-no in his application. He opened several of the bags and inserted a
magnet. The magnet came out covered in a grayish type material. At first, my vendor was not sure what
this was. After a few days, they got back to me and reported that it was biotite in the perlite which
apparently is magnetic. After 20 years of selling this product this is a first and I am not sure what to tell
my customer. They picked it up because of the discoloration and I am concerned that many more will as
well. I guess the question is: is perlite laced with biotite ok to use as a filter aid? Can it be removed by
the expander?
A1: Expanded perlite is listed as a nuisance dust. It is basically inert. It has FDA approval to be fed to
animals after it has filtered out organics such as yeast and hops and wine skins. I have attached our
Perlite Bulletin on the health information on perlite. Hopefully this will help provide a better
understanding of working with perlite. The perlite industry does recommend the use of masks when
handling it. It does cause one to cough a bit.
Q2: If we open a bag of expanded perlite, insert a long handled magnet, swirl it around, and withdraw it,
should the perlite particles stick to the magnet or not? Is perlite magnetic?
A2: No perlite should stick to the magnet especially with very fine expanded perlite. I have never heard
of this issue before. There is a small amount of iron in perlite but most of it is bonded into the silica.
However, as the perlite mines closer to a ryolite section, the iron content may increase a bit - unlikely
but perhaps possible. Even so, it may not be magnetic in nature. Per my discussion with Laird, he
indicated there might be a health concern if an iron was present. All the various perlites that the
Institute has tested have not indicated it. This is why I sent the earlier bulletin on health. If material is
collected by the magnet it should be a super fine powder. If there are distinct particles, it would most
likely be a contaminant from the processing equipment in the suppliers system meaning a deteriorating
problem exists that they are not aware of. I would recommend sampling bags of material from each of
your suppliers to determine if it is specific to one of them. Then contact them to let them know.
Bulletin: Health-Effects_Perlite
Q: We are transloading your #66 Perlite ore and I would like to know the bulk density in lbs. /ft3.
A: Perlite ore is in the range of 60 - 70 #/ft3.We, the Perlite Institute, is a technical association so the
material referenced is not for us. You will need to address the correct user.
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: We have a customer looking to use the perlite product in concrete for insulation. They have an
underground water line that is too close to the surface. I am trying to figure the actual weights for one
(1) cubic yard of concrete. We will be delivering the concrete to the site in a concrete truck. How do I
determine the actual weights per yard of the materials; perlite, fine agg, coarse agg, water, cement,
admix, etc. Also do you recommend a certain mix design for this intended use?
A: The mix required is dependent on the strength and insulation desired. I have attached our PI bulletin
on various mixes for concrete that may be of help in selecting the mix. One is also for underground pipe
insulation which may be similar to what you are doing. The admix is really dependent on the local
environment so it is best to check with your local supplier to see what they find best for the area. I have
also included a bulletin on the handling of light weight cements. Expanded perlite is glass bubbles and
can be broken down by aggressive handling.
Bulletins: Perlite-Concrete; Transit-Mix-Perlite; Perlite-Concrete_Insulating-Underground-Pipe-Ducting
____________________________________________________________________________________ Q: Just checking the chemical compatibility of Perlite with PVC Plastic and Viton elastomer seal. A: Perlite is basically inert. Expanded microsphere perlite is used as filler in many plastics. I have attached our Perlite Institute bulletin on the physical characteristics of perlite which provides more information on it. Bulletin: PhyscialCharacteristics_Perlite
Q1: I am an architect in Arizona and I am currently designing a small house in Town of Williams in North West Arizona. The owner wishes to use CMU exterior wall to have the Split Face CMU effect in the interior of his house. The City requires R-19 wall insulation since this area considers as cold climate and needs proper insulation. The Builder suggests using your product, Perlite Insulation, as our one and only insulation. Here are my questions: 1- Does this product work equivalent of the continuous R-19 Batt insulation? 2- What happens where the grout is used? 3- How do we work around masonry beams/ headers? 4- Do you have ESR # and product cut sheets for the City? A1: The R rating of perlite loose fill CMUs is dependent on the density and size of the block. – I have attached a bulletin on block and fill and different block. The data indicates one could obtain close to a R 9 factor depending on the block. It would not obtain the R 19 desired. Q2: Is there any literature showing the ESR record for your product? A2: I could not find any ESR ratings for perlite plasters. However, the attached Perlite Institute bulletin on such products shows the fire ratings that can be achieved with such products when applied in various thicknesses. Bulletin: Perlite-looseFill-insulation; Lightweight-Perlite-Aggregate_Cement-And-Gypsum-Plasters
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: We are member of Perlite Institute and we could not find in Perlite home information about The U.S.
??
A: I have attached our latest Perlite Institute bulletin on health effects as well as an older more detailed
document on it as well.
Bulletin: Health-Effects_Perlite; HE
Q: Can perlite be used to pack peaches for a few days while transporting them across country by car? A: Coarse, expanded perlite should be able to be used as packing for transport. The finer grades of perlite are very fluid and would likely allow the peaches to settle down to the bottom. The expanded perlite would insulate a bit however, it seems like a cooler would be better suited for cooling. This is the first I have heard of such an application so we have no data to support our opinion.
Q: I downloaded your publication "Overview of Perlite Concrete" and plan to make test batches from
your table of 11 mix designs on page two. The sixth column is labeled "Admix (A&B)" with superscript A
assigned to "Air Entrainment" and superscript B assigned to 'Pozzolith 300-N (fl.ox.)." I do not
understand the numbers regarding air entrainment. The first row, for example, shows a 1:8 ratio of
cement to Perlite that uses 16 gallons of water and "28" admix A. What value does the "28" refer to?
Would I be looking for a percentage of air entrainment or for something else? Also, the eighth row
shows a 1:3 ratio of cement to Perlite that uses 7.5 gallons of water and an admix of "7." There is no
superscript assigned to the "7." Does the "7" refer to air entrainment or to pozzolith? I purchased Perlite
from Willamette Greystone and ordered Fritz-Pak air entraining admixture from our Mason's Supply. I'll
be ready to begin the test batches as soon as I understand the meaning of the air entrainment numbers
in column 6 of your table.
A: The perlite concrete bulletin lists some typical blends that are used in such mixes. The key element is
the impact of various perlite/concrete mixes. It is recognized that mixes are made specifically for the
type of environments that they are used in. So, the specific air entrainment, pozzolan and admix are just
generic. One should check with their local cement supplier to see just what they normally use for the
environment that exists in their area. These minor ingredients do not have a significant impact on the
strengths of the mix.
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: I'm an architect in Eugene, OR. We're doing 10,000 sf of kennel space with block exterior walls that
must have 50 percent of the cells perlite filled to meet code. This is a heated facility just slightly below
"human" standards for heating being provided. The interior has a huge air flow requirement and is
highly ventilated. I understand that siliconized perlite is long gone from the industry...my specs are old, I
guess! I was hoping to help with moisture absorption by using this product. Since we are going to need
to use the "standard" product now, should I be too concerned about providing supplemental drainage
for the perlite filled cells? This would be very tedious to do. We plan on a very good seal coat on the
exterior of the block and have a vapor barrier like finish being provided on the interior. This may do
quite well without any serious moisture absorption worries. Our project starts block work in less than
two weeks; your advice would be appreciated.
A: Most all the expanded perlite producers discontinued making silicone coated material more than 10
years ago. It is no longer required by ASTM C549. You may want to check to be sure the contract is up to
date on its requirements. While the silicone coated product is hydrophobic, it does not affect any of the
insulating properties or do anything that users experienced. Consequently, it only added cost to the
product and no real value. Supplemental drainage would not be recommended. Expanded perlite flows
like water and flows to any open areas. This is why any openings are to be sealed before the perlite is
added. No one wants piles of expanded perlite repeatedly developing near any opening.
Bulletins: Perlite-looseFill-insulation; Thermal-Performance_Perlite-Insulated-Masonry
Q: My name is Kim Stewart and I work with Therm O Rock West. The president of Therm O Rock, Ron
Dobkin, directed me to your offices and they directed me to you. We have been asked by one of our
vermiculite customers to provide a comparison of all of the different sorbents. Obviously, we’d like to
compare perlite and vermiculite, since Therm O Rock West produces both. We would also like to
compare to poly absorbents, dried peat moss, coir, DG, etc. Does either the vermiculite association or
the perlite association have any such info? Can you direct me to another organization that might
provide that info? We’d prefer that the info be provided in a chart and cover absorbency, cost,
chemicals or materials absorbed, safety, etc.
A: Nice to hear from you. We are just about finished with a new bulletin on water holding capability of
various perlites [attached is the last draft of it]. Hopefully, this will help. The second one is for specific
uses of perlite for water quality. I thought it might be of interest to you as well. Both of these are the
latest drafts. A few refinements may yet be made before we post them for everyone. The Perlite
Industry does not have corresponding information on vermiculite.
Bulletins: Perlite-Water-Holding-Capacity-07112018; Perlite-for-Water-Quality- 07.11.2018
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: I am offering affordable housing solutions to the rural poor in India. Here we offer 30 sq. mtr single
story homes as shown in the attachment. We are looking for a reliable, low-cost terrace coating solution
which can insulate the home. The terrace has lintels hollow blocks and then screening and a 50 mm
concrete layer. Can we mix perlite and eps/fibers in this mix to get a minimum R value of 40? Please
suggest a member of your organization who can assist me in the above designing.
A: Attached are a number of our Perlite Institute bulletins on perlite plasters. However, it is unlikely that
an R value of 40 for the wall could be obtained only with the plaster. I also included one on perlite loose
fill since the wall is hollow. Since you are striving for maximum insulating values, it seems that this
should be considered as well.
Bulletins: Lighweight-Fiber-Reinforced_Perlite-Cement-Plasters; Lightweight-Perlite-Aggregate_Cement-
And-Gypsum-Plasters; PerlitePlaster-draft5-AGK-07.04.18; Thermal-Performance_Perlite-Insulated-
Masonry; Perlite-looseFill-insulation
Q1: I have specification that requires pumice or slag to create a one and three hour fire rated wall. Is
there any perlite made with pumice that would create a one or three hour fire wall?
A1: Attached are a couple of our Perlite Institute bulletins on light weight cement plasters that can be
applied to block walls that yield four hour fire ratings. I have also included our light weight cement
bulletin which illustrates the strength that can be expected from various mixes. Attached is another
bulletin from one of our members who does a great deal of light weight cement applications. It may
provide some additional information that maybe useful to you.
Bulletins: Lightweight-Perlite-Aggregate_cement-And-Gypsum-Plasters; Thermal-Performance_Perlite-
Insulated-Masonry; GulfPerliteConstructionalBrochure
Q2: Let me ask this question, what is the minimum thickness of perlite that can be used in a 8” and 12”
cmu to achieve a three hour wall. Attached document and table 1 is information my engineer supplied
to me, but it does not list perlite. Do you have any literature that supports a minimum thickness of
perlite?
A2: I am not sure what the meaning is of minimum thickness. Expanded block fill flows like water. It fills
up the entire open cavity so the thickness of the perlite bed would be equal to the width of the open
core. The four hour rating was determined according to UL standards. I am not sure what additional
information would be appropriate until I understand the thickness question.
The fire rating for filled block certainly should achieve the targeted one to three hr. rating and then
some. Shown below is information from the Silicone perlite loose fill bulletin – first page near
bottom. Over the years it has been recognized that silicone coated loose fill performs just like uncoated
material from an insulating and fire rating standpoint. Consequently, few expander perlite producers
make any silicone treated material anymore.
Bulletins: Silicone-Perlite_Loose-Fill-Insulation; Perlite-looseFill-insulation
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q1: I'm a general contractor in Ontario Canada. I recently was award a renovation project which
includes removal of textured ceiling or popcorn ceiling as some call it. My concern is this: I haven't been
able to get a direction or clarification if the Perlite in the textured ceiling is asbestos based and if proper
asbestos remediation is necessary, or would proper respiratory masks and dust control would suffice.
The homeowner had it sent to Pro-Lab which is located in Florida. They confirmed Perlite in the
texture. Also a material called binders was also in the lab report. Not sure if this is a by-product of
Perlite. If at all you can help with this dilemma it would be greatly appreciated or if you can direct me in
anywhere to resolve this matter.
A1: You are in luck! Expanded perlite does NOT contain any asbestos at all. It is considered a nuisance
dust. Even so, we recommend that people wear respirators to minimize the exposure to the dust. Perlite
does make one cough. I have attached our bulletin on the health effects of perlite for additional
information for you.
Q2: Thank you very much for the clarification regarding my dilemma. I appreciate your time and I'm sure
the homeowner will as well. We can now move forward with this project.
A2: I am glad we could be of help. Just be sure to have the guys wear respirators or they will be
coughing a lot. My guess is the guys do this normally anyways. I even cough when I go to a perlite plant.
It normally takes a day or so before the sensitivity to the dust subsides.
Bulletin: Health-effects_perlite
Q: I work for engineering and construction company, CDMG/Stevens. We would like to fill the cells of
rather large existing block building. The building is constructed of 12” wide CMU with a bond beam and
roof already installed. Would it be possible to drill holes in the top cells directly below the bond beam
and pneumatically blow in the perlite insulation? If so, do you know of what equipment would be used
for this process? Any other ways of installing the perlite in a retro fit condition that you could suggest
would be greatly appreciated.
A: I am not aware of any such equipment but will talk to some of the Perlite Institute members who
supply this material. I should hear back from them by Tuesday. The problem of blowing perlite is how to
get rid of the air without making the world go dusty. Expanded perlite flows like water. It may be that an
elevating mechanism that allows the perlite to flow down by gravity would do the job. This is why I need
_____________________________________________________________________________________
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q1: We are interested in using perlite insulation for concrete roof application for the Point Fortin
Hospital Project. Our Client is the Government of Trinidad and Tobago.
The area to be insulated is 5,000 square meters and we need to achieve a u-value (British) of 0.48.
We kindly ask for your advice on the following:
The thickness of the insulation using the Perlite required to give the u-value The mixed design of the cement/water/perlite/sand, ratio Application procedures Recommended Supplier (preferably from the USA due to shipping cost). No. of bags required for the complete works (based on the area and the recommended
thickness). And if possible the average cost per bag
A1: I have attached several of our Perlite Institute bulletins concerning roof decks. Normally, people use
a 6:1 ratio for the mix to get the desired strength as well as insulating properties in addition to the
weight for areas with high winds. This includes typical mixes with sand and filler. The lower the U value,
the better the insulation. The bulletin illustrates the impact of various density mixes. The more
perlite, the lower the U value and the better. [I am not aware of anyone who installs less than 2 inches
[5 cm] thickness of light weight cement so I would not recommend going with a thinner coat just for the
U factor. I also included a bulletin on how to mix and transport the mixture since perlite is hollow glass
bubbles and will break with agitation. The Perlite Institute does not sell or supply expanded perlite. It is
a composition of independent members who supply material in their respective areas. Consequently, we
cannot give you any indication as to the pricing of material. This has to be done directly with whomever
you select. Our Perlite Institute web site has a directory on the homepage which hyperlinks to members
in the selected area. You can find member contact information by clicking on the white dots on the map.
My initial thought is that a member that is close to the ports may be able to help you. You would have to
contact them for more information.
Q2: We just have one question, can the perlite mix you suggested (6:1 ratio) be mixed with a water
proofing compound (Nexseal water proofing admixture) as per the attached.
A2: This is the first I have encountered that additive. The description certainly appears to be a good
material. I would recommend you contact the Nexseal supplier and specifically ask them their
recommendations for light weight cement mixes in your environment. Many admixes are for certain
_____________________________________________________________________________________
Q: Per our phone conversation, would you please send us any information or photos re perlite puffer?
A: I have attached a sketch of a typical perlite expander unit to give you an overview of the type of
system is normally used to expand horticultural perlite. Most all users install these inside a building with
the exception being if it is in a warm environment. Changes in the exterior weather can have quite an
impact on the performance of the expanders. Sized ore is normally purchased in 20 or 100 ton quantities
Perlite Institute Technical Q&A’s June 2018 – August 2018
at a time. The ore which is 65 #Ft3 is normally stored in round silos. They have to be large enough to
handle several incoming loads. There are some locations where the ore is stored on cement enclosed
pads from which scoops of ore are then taken to a feeder for metering to the expander. This involves
more labor and mobile equipment. There are two perlite institute members who fabricate entire perlite
expansion units. More information can be obtained at their websites
http://www.inconcorp.com/equip/equip.htmhttp://www.inconcorp.com/equip/equip.htm
http://www.silbrico.com/PerliteEquipment/plantexptech.html
Most horticultural expanders produce about 1 TPH to produce about 325 Ft3/hr. of material at about
6#/Fr3. The expanded perlite is glass bubbles which are friable and care needs to be taken in
transporting them to the use point. Any producers screen the expanded product to control the particle
size of the desired product. This obviously results in the generation of unwanted by-product that has to
be dealt with as well.
Things get a lot more complex the further one gets into a project so feel free to contact me.
Bulletins: Typical Perlite expander system (excel doc); Perlite-GradesSizes
Q1: I am from the country of Georgia. I am going to build house and have two questions about building
materials.
1. Do you recommend building a house with Perlite block, or is it better to use perlite only for loose
fill insulation?
2. Do you think it will have an insulation effect if I fill pumice block holes with perlite?
A1: I have attached a few of our Perlite Institute bulletins on light weight blocks and insulation of those
blocks. The light weight blocks made with perlite filler provide better insulation than heavy density
blocks. The key is how much strength is needed, which should determine the density of the blocks. The
next issue is block size. Larger blocks have greater insulating properties than the smaller ones. In
response to your second question, my guess would be that a pumice block would be denser than a light
weight block of the same size made with perlite. From an insulating standpoint I would say the lighter
the block the better. Of course, this does NOT take into account economics which are different for every
area.
Q2: Two more questions…
1. I am going to use Blocks on frame construction and because of this Perlite block strength is absolutely
enough for now. However, I am concerned about what will happen after 15-20 years. Do you think
Perlite block life expectancy will be similar as common concrete or pumice blocks?
Perlite Institute Technical Q&A’s June 2018 – August 2018
2. Do you think Perlite blocks are as reliable as ordinary concrete blocks during earthquakes?
A2: I have never encountered any issue relative to the durability of cement blocks so it is unlikely that in
15-20 years there will be any issue with the LWD blocks. As to earthquakes, that is normally an issue for
the local area relative to what could happen. Each area has their own criteria for their areas so that is
something you will need to check with your local authorities. I would suggest that one would need to
strategically locate rebar in both the vertical and horizontal areas to protect for earthquake
activity. Again, this is a suggestion and this matter is something that should be discussed with your local
authorities.
Q1: I am developing a blanket cement based plaster for applications in Australia to increase thermal
barrier on external walls. My perlite percentage is 20 percent of the formula with application 10mm.
Would you have any support information to assist my development? Can you help me my 1:5 cement to
perlite by volume 15 mm thick wall plaster is not giving me enough R value?
A1: I have attached our PI bulletin on perlite/cement mixes which shows the expected R value for such
mixes when they are 1” thick, about twice what you have applied.
I also attached our Perlite / cement plaster mixes that are used for coating block and steel. Several
coatings are normally used. The data on these is directed primarily on the fire rating that results and not
the insulation. I do not know what R rating was expected, so I cannot really comment on what you
obtained verses what was expected.
Q2: I can’t find the R Values in your P1 Bulletin on Perlite Plaster, please advise.
A2: I figured out why you could not find the R values on the plaster bulletin - they are not there! The
majority of the effort with plasters is their impact on fire rating. The Light Weight Perlite Cement
bulletin shows the K value for various formulations. The inverse of K is the R factor for 1 inch thick
coverage. So, the K factor of a 1:5 ratio of cement is 0.71. The inverse of this for the R rating for 1 inch
of coverage is 1.41 R. Since you have a 155 mm thickness, that is equivalent to .61 of an inch which then
translates to an R factor of 0.86.
Q3: Can you give me the metric value of your 15 mm R value on 5:1 formulation
A3: The K factor for a 5:1 ration is a unit of insulating value is 0.71 for 1 inch [25,4 mm] thickness. This
equates to a 1.408 R factor for 1 inch thickness. Since 15 mm thickness is 0.59 percent of an inch, the R
factor would be reduce by this amount yielding a R factor is 0.8 .
Bulletins: Perlite-Concrete; Lightweight-Perlite-Aggregate_Cement-And-Gypsum-Plasters; Thermal-
Performance_perlite-Insulated-Masonry
Q: I have read with interest your article titled "Perlite for Non-Evacuated Cryogenic and Low
Temperature Service" regarding the physical character of expanded Perlite:
Perlite Institute Technical Q&A’s June 2018 – August 2018
In relation to the same, I would be grateful for any clarification you can provide on the below queries
regarding cryogenic Perlite:
a. Bearing in mind its size, would cryogenic perlite get caught in a mesh of 0.84mm diameter if the perlite was suspended in liquid cargo (LNG) which was being pumped through that mesh at a significant rate (for example 10,000m3/hr) (and afterwards flushed through by 5,000m3 of cargo without any perlite suspended within it)?
b. Could perlite float on convection currents (i.e. in a gaseous environment), and if so, would it be able to reach a height of 30m?
A: A- It is unlikely that perlite would be suspended in the LNG to start with. Only about 10 percent of the
expanded cryogenic perlite is larger than the 0.84 mm [20 mesh] size of the mesh being used. I would
suspect that if there was any perlite in the LNG, only a small portion would be caught by the
screen. Furthermore, it could easily be broken down by the pressure involved in pumping through the
screen. You did not mention the pressure involved in the pumping. That information would help. After
that, I can check with some of our Perlite Institute members who regularly work in the cryogenic area
just to be sure.
B- Expanded cryogenic perlite is 2.5 to 5 Pounds/ft3. It should not float in a gaseous environment. I
certainly have never heard of that happening.
Q: I am a Research Engineer with Saint-Gobain Corporation and am currently leading a project to
improve our expanded perlite quality. I have several questions about equipment design and best
practices and I was hoping to be able to discuss them with you. Please let me know if you would be
willing to work with me on this and hopefully we can schedule a phone call.
A: Every system is unique as well as the application. There is no “right” way to expand perlite, just a
variety of ways. There are some basics which hopefully, can help you with which is why it is good for us
to talk.
Here are a few of the things we will be covering in our phone call this afternoon:
What is the expanded product being used for The ore grade being used The target density The production rate The type of furnace being used The draft on the system An estimate of the fuel per hour or ton An estimate of the air / fuel ratio
Q: We would like to know the exact density and water holding capacity of our perlite in addition to
other tests. I am having a hard time finding a lab that will run these tests.
A: It is rare that any perlite producer will ever use an outside lab since most all testing is done by them. Consequently, I am not aware of any such facilities. The Perlite Institute is currently developing
Perlite Institute Technical Q&A’s June 2018 – August 2018
information on water holding capacity of expanded perlite. Normally it ranges from three to eight times the weight of the expanded perlite. The perlite’s water holding capacity is dependent on the ore source, the size, density, and fractional density of the expanded perlite. We expect to have a bulletin on this in the near future. I will have to make a note to send you that as soon as it is available.
As to density testing, listed below is our Perlite Institute test method for this that most everyone uses. Note: loose weight density is much different than the packed density of the product. The type of packer has a great deal of impact on how much air is entrained in the product so bag size is NOT an indicator of the effective loose weight density.
LOOSE WEIGHT DETERMINATION OF EXPANDED PERLITE PI Designation: 200- 77 SCOPE This method covers the determination of loose weight density of expanded perlite. SIGNIFICANCE OF TEST The density to which a perlite ore is expanded controls many of its properties. It is important to be able to measure this density as a control method. APPARATUS (a) Shovel or scoop. (b) Measure of known capacity, between 1 and 2 liters. (c) Balance or scale sensitive to within 0.1 percent of sample weight to be tested. PROCEDURE (a) The measure shall be filled to overflowing by means of a shovel or scoop, the perlite being discharged from a height of not to exceed 50 mm above the top of the measure. Care shall be taken to prevent, so far as possible, segregation of the particle sizes in the sample. (b) The surface of the perlite shall then be leveled off with a straight edge. (c) The net weight of the perlite in the measure shall be determined. CALCULATIONS The loose weight in kilograms per cubic meter is determined as equal to: Weight of perlite sample in grams/Volume of perlite sample in milliliters*1000 The loose weight in pounds per cubic foot is determined as equal to: Weight of perlite sample in grams/Volume of perlite sample in milliliters*62.4
Q2: Thank you so much for your response. I appreciate the information about performing the bulk
density (loose weight) test. I am still curious of where you got all the information on your website for
such things as Specific Gravity, Refractive Index, Ph., Free Moisture, and all of the "Typical Elemental
Analysis.” Yes, I would be really interested in the developing information on water holding capacity of
expanded perlite. Just curious of how you know that the water holding capacity ranges from three to
eight but don't have a test for it? I have ran my own version of "water holding" capacity but would like
to know the actual test so we can compare apples to apples. I have spoken to several labs and none of
them will run this test on perlite because they don't know what the test is. We would love to join the
Perlite Institute in the future but would like to see more info that shows how the data was obtained.
A2: The following is a list of the standard Perlite Institute test methods which is being revised.
CONTENTS Page
PI 108-77 Method for Bulk Box Car Sampling of Sized Perlite Ore… … … … …
PI 109-77 Method for Sampling Sized Perlite Ore From Hopper Cars… … … …
PI 110-77 Sampling Perlite… … … … … … … … … … … … … … … … …
Perlite Institute Technical Q&A’s June 2018 – August 2018
PI 111-77 Preparation of Perlite Sample for Testing By Coning and Quartering
Method… … …
PI 112-77 Preparation of Perlite Sample for Testing by Splitter or Riffle Method
PI 113-77 Sieve Analysis of Fine Materials… … …
PI 114-77 Sieve Analysis of Expanded Perlite Volume Basis… … … … … … ..
PI 115-77 Sieve Analysis of Expanded Perlite Weight Basis… … … … … … ...
PI 116-77 Fractional Density of Expanded Perlite..
PI 117-77 Wet Screen Analysis… … … … … … … ...
PI 118-77 Determination of Free and Combined Moisture in Perlite…… … … ..
PI 200-77 Loose Weight Determination of Expanded Perlite… … … … … … ..
PI 201-77 Compacted Density… … … … … … … … .
PI 300-77 Determination of "Floats" and "Sinks" in Expanded Perlite… … … .
PI 301-80 Percent Nonexpansibles in Perlite… … ..
PI 303-77 Water Repel1ency Test… … … … … … ...
PI 305-77 Yield Test for Perlite Aggregate… … … .
PI 306-80 Compaction Resistance Test… … … … ...
PI 307-77 Perlite Ore Expansibility Test… … … …
PI 400-77 Setting Time of Gypsum Plaster… … …
PI 401-77 Plaster Coverage Test… … … … … … …
PI 501-83 Method for Determination of Wet Density
And Relative Water Permeability of Powder Type Filter Aids… … … … … …
ASTM Specifications…………………………………………………………..
CEN Specifications……………………………………………………………..
We are still in the midst of developing test methods for the amount of water that various sized
expanded perlites from various ore deposits can hold. Until we have completed that, we should not
make a “tentative” test method available to any users. I will make a note to send you a copy when that
is complete.
Q: I have a 100 year old house with planks on the interior walls and clapboard on the exterior walls. I hesitate putting blown in insulation like fiberglass, rock wool or cellulose because there's no vapor barrier. The house in in hot Central Texas near Austin, so I do want insulation and was wondering what you thought of using Siliconized perlite? Also, if it is a good idea, is there a blower to put it in the walls stud cavities? I would take the top plank off for access.
A: A silicone coated perlite is not needed for this type application. It simply makes the material
hydrophobic which is not needed in such an application and is more costly. I have attached our bulletin
on block fill which illustrates the insulation capability of perlite at various thicknesses. The expanded
perlite for insulation pours like water. Therefore, it is mandatory to seal any cracks or it will simply flow
out. This includes the electrical outlet boxes. The expanded perlite is considered a nuisance dust but
Perlite Institute Technical Q&A’s June 2018 – August 2018
makes one cough. It is standard practice even in the production facilities to wear respirators. It is normal
for people to pour the perlite from 2.5 or 4 cubic foot bags into the areas. Pneumatic conveying like
done with cellulose does not work. You can find Perlite Institute perlite suppliers in your area by going
to the directory on www.perlite.org.
Bulletin: Perlite-looseFill-insulation
Q: A few of us from the Michigan Technological University Concrete Canoe Team stopped in at Midwest
Perlite, Inc. in Appleton, WI to get some information about perlite for use in our boat next year. One of
the rules we have to follow covers our aggregate blend and requires us to include an ASTM C330
compliant aggregate as at least 25 percent of the aggregate volume in our mixture. We are really
interested in using perlite because of its low density, but need documentation that it has been lab
certified to meet the ASTM C330 requirements. Midwest Perlite told us that if anyone can figure this
out, you're the man to ask, so we were wondering if you have the documentation already or if you knew
of anywhere one could find it. Let me know what you think.
A: The following is from a David Yarbrough from the ASTM. It is his opinion that the ASTM 332 tests
would be more appropriate than the 330 per below:
Incidentally, they also will do lab testing if needed.
I recall providing some perlite for a concrete canoe project at Tennessee Tech several years ago. As far
as I know the project was successful. C330 and C332 are somewhat different. C330 is for structural
concrete. C332 is for insulating concrete. The objective in the case of the canoe project is lightweight
concrete – this would be in the category covered by C332. C332 does not appear to have mechanical
property requirements. A factor with low-density concrete is reduced shear and compressive strengths.
These properties are related to the composition (amount of perlite used). I recall the very low density
(high perlite content) had very low shear resistance (not good for a canoe). My guess is that the
concrete density should be greater than 40 PCF (a guess). The concrete canoe contest is related to
engineering departments (I believe this is still the case). The students should make some candidate
mixtures and test the 28-day compressive strength. I would suggest a need for numbers of at least 250
PSI. Shear strength is more crucial – don’t want the canoe to shear into pieces when lifted. The purpose
of the contest is for the competitors to do some materials research. I would consider some light-weight
reinforcing material – like hollow PVC pipe or tubes also, low density concrete has to be sealed against
water penetration. (obvious, I suppose). In my opinion C 330 is not related to the project.
Q2: Is there a published criterion for maximum amount of moisture content (% scale) for perlite based
roof insulation boards, or alternatively, max content allowed before the board cannot be covered by
roofing materials?
A2: Expanded perlite used in insulating boards does not have an issue with water content. Before sized
perlite is expanded into the bubbles used in board, it has about three percent moisture content. About
two percent is free water and one percent combined water which is bond. The conversion process is at
Perlite Institute Technical Q&A’s June 2018 – August 2018
about 2,000 F so any free water is liberated as is most of the bond water. Consequently, there are no
concerns about its water content. Those who make insulating boards use proprietary processes which
incorporate the perlite with other ingredients. I would suggest that you contact the producer of the
perlite insulating board in question and ask them specifically if there would be any concern about their
material. They should have such information. The Perlite Institute does not have any information due to
the many different formulas that are used in so many different markets. Many incorporate expanded
perlite into their mixes to make light weight cements which can then be used for roof decks. These
obviously include quite a bit of water content in making up the concretes. I have attached a couple of
our Perlite Institute bulletins which illustrate these points.
B: Perlite-Concrete; Perlite-Insulating-Concrete_Roofdeck; Perlite-Insulating-Concrete_Roofdeck-Specs
Q: I am a home owner who is building his own home. I built the floor to be able to have 1 ½ inch of 15
lb. per sq. ft. (120 lbs. / cubic ft.) lightweight concrete poured over the pex tubing. I have viewed your
organizations web site with regard to the various mixes. The question I have is in regards to the type of
perlite. I live in the Seattle area and most of the perlite in the area is sold for agricultural use, some is
sold by masonry suppliers for insulation between cement blocks. In talking to the masonry supplier they
are unaware of its use in lightweight concrete. Is there a particular grade or type that I should be looking
for?
A: Uncoated masonry fill can be used for making light weight cements [Attached is our bulletin on
perlite grade sizes]. Coated material is hydrophobic and will not wet into cement. It is rare for this to be
used anymore but something to be aware of. Some producers do make a slightly heavier large density
expanded perlite for light weight cements for large jobs such as roof decks. Supreme Perlite is located in
Portland and can be contacted if need be. Their information is located on www.perlite.org. Also
attached is a bulletin on mixing perlite. Perlite, being light weight glass bubbles, will break down with
heavy mixing so one has to be careful of this property
B: Perlite-GradesSizes; Perlite-Concrete; Transit-Mix-perlite
Q1: We buy truckloads of perlite for pre-coating baghouse filters. It always works and does a good
job. A few days ago, I got a call from an end user who noticed that the color of the perlite was slightly
darker that what he always gets. His suspicion led him to believe that there were magnetic particles in
the product which is a no-no in his application. He opened several of the bags and inserted a
magnet. The magnet came out covered in a grayish type material. At first, my vendor was not sure what
this was. After a few days, they got back to me and reported that it was biotite in the perlite which
apparently is magnetic. After 20 years of selling this product this is a first and I am not sure what to tell
my customer. They picked it up because of the discoloration and I am concerned that many more will as
well. I guess the question is: is perlite laced with biotite ok to use as a filter aid? Can it be removed by
the expander?
A1: Expanded perlite is listed as a nuisance dust. It is basically inert. It has FDA approval to be fed to
animals after it has filtered out organics such as yeast and hops and wine skins. I have attached our
Perlite Bulletin on the health information on perlite. Hopefully this will help provide a better
understanding of working with perlite. The perlite industry does recommend the use of masks when
handling it. It does cause one to cough a bit.
Q2: If we open a bag of expanded perlite, insert a long handled magnet, swirl it around, and withdraw it,
should the perlite particles stick to the magnet or not? Is perlite magnetic?
A2: No perlite should stick to the magnet especially with very fine expanded perlite. I have never heard
of this issue before. There is a small amount of iron in perlite but most of it is bonded into the silica.
However, as the perlite mines closer to a ryolite section, the iron content may increase a bit - unlikely
but perhaps possible. Even so, it may not be magnetic in nature. Per my discussion with Laird, he
indicated there might be a health concern if an iron was present. All the various perlites that the
Institute has tested have not indicated it. This is why I sent the earlier bulletin on health. If material is
collected by the magnet it should be a super fine powder. If there are distinct particles, it would most
likely be a contaminant from the processing equipment in the suppliers system meaning a deteriorating
problem exists that they are not aware of. I would recommend sampling bags of material from each of
your suppliers to determine if it is specific to one of them. Then contact them to let them know.
Bulletin: Health-Effects_Perlite
Q: We are transloading your #66 Perlite ore and I would like to know the bulk density in lbs. /ft3.
A: Perlite ore is in the range of 60 - 70 #/ft3.We, the Perlite Institute, is a technical association so the
material referenced is not for us. You will need to address the correct user.
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: We have a customer looking to use the perlite product in concrete for insulation. They have an
underground water line that is too close to the surface. I am trying to figure the actual weights for one
(1) cubic yard of concrete. We will be delivering the concrete to the site in a concrete truck. How do I
determine the actual weights per yard of the materials; perlite, fine agg, coarse agg, water, cement,
admix, etc. Also do you recommend a certain mix design for this intended use?
A: The mix required is dependent on the strength and insulation desired. I have attached our PI bulletin
on various mixes for concrete that may be of help in selecting the mix. One is also for underground pipe
insulation which may be similar to what you are doing. The admix is really dependent on the local
environment so it is best to check with your local supplier to see what they find best for the area. I have
also included a bulletin on the handling of light weight cements. Expanded perlite is glass bubbles and
can be broken down by aggressive handling.
Bulletins: Perlite-Concrete; Transit-Mix-Perlite; Perlite-Concrete_Insulating-Underground-Pipe-Ducting
____________________________________________________________________________________ Q: Just checking the chemical compatibility of Perlite with PVC Plastic and Viton elastomer seal. A: Perlite is basically inert. Expanded microsphere perlite is used as filler in many plastics. I have attached our Perlite Institute bulletin on the physical characteristics of perlite which provides more information on it. Bulletin: PhyscialCharacteristics_Perlite
Q1: I am an architect in Arizona and I am currently designing a small house in Town of Williams in North West Arizona. The owner wishes to use CMU exterior wall to have the Split Face CMU effect in the interior of his house. The City requires R-19 wall insulation since this area considers as cold climate and needs proper insulation. The Builder suggests using your product, Perlite Insulation, as our one and only insulation. Here are my questions: 1- Does this product work equivalent of the continuous R-19 Batt insulation? 2- What happens where the grout is used? 3- How do we work around masonry beams/ headers? 4- Do you have ESR # and product cut sheets for the City? A1: The R rating of perlite loose fill CMUs is dependent on the density and size of the block. – I have attached a bulletin on block and fill and different block. The data indicates one could obtain close to a R 9 factor depending on the block. It would not obtain the R 19 desired. Q2: Is there any literature showing the ESR record for your product? A2: I could not find any ESR ratings for perlite plasters. However, the attached Perlite Institute bulletin on such products shows the fire ratings that can be achieved with such products when applied in various thicknesses. Bulletin: Perlite-looseFill-insulation; Lightweight-Perlite-Aggregate_Cement-And-Gypsum-Plasters
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: We are member of Perlite Institute and we could not find in Perlite home information about The U.S.
??
A: I have attached our latest Perlite Institute bulletin on health effects as well as an older more detailed
document on it as well.
Bulletin: Health-Effects_Perlite; HE
Q: Can perlite be used to pack peaches for a few days while transporting them across country by car? A: Coarse, expanded perlite should be able to be used as packing for transport. The finer grades of perlite are very fluid and would likely allow the peaches to settle down to the bottom. The expanded perlite would insulate a bit however, it seems like a cooler would be better suited for cooling. This is the first I have heard of such an application so we have no data to support our opinion.
Q: I downloaded your publication "Overview of Perlite Concrete" and plan to make test batches from
your table of 11 mix designs on page two. The sixth column is labeled "Admix (A&B)" with superscript A
assigned to "Air Entrainment" and superscript B assigned to 'Pozzolith 300-N (fl.ox.)." I do not
understand the numbers regarding air entrainment. The first row, for example, shows a 1:8 ratio of
cement to Perlite that uses 16 gallons of water and "28" admix A. What value does the "28" refer to?
Would I be looking for a percentage of air entrainment or for something else? Also, the eighth row
shows a 1:3 ratio of cement to Perlite that uses 7.5 gallons of water and an admix of "7." There is no
superscript assigned to the "7." Does the "7" refer to air entrainment or to pozzolith? I purchased Perlite
from Willamette Greystone and ordered Fritz-Pak air entraining admixture from our Mason's Supply. I'll
be ready to begin the test batches as soon as I understand the meaning of the air entrainment numbers
in column 6 of your table.
A: The perlite concrete bulletin lists some typical blends that are used in such mixes. The key element is
the impact of various perlite/concrete mixes. It is recognized that mixes are made specifically for the
type of environments that they are used in. So, the specific air entrainment, pozzolan and admix are just
generic. One should check with their local cement supplier to see just what they normally use for the
environment that exists in their area. These minor ingredients do not have a significant impact on the
strengths of the mix.
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: I'm an architect in Eugene, OR. We're doing 10,000 sf of kennel space with block exterior walls that
must have 50 percent of the cells perlite filled to meet code. This is a heated facility just slightly below
"human" standards for heating being provided. The interior has a huge air flow requirement and is
highly ventilated. I understand that siliconized perlite is long gone from the industry...my specs are old, I
guess! I was hoping to help with moisture absorption by using this product. Since we are going to need
to use the "standard" product now, should I be too concerned about providing supplemental drainage
for the perlite filled cells? This would be very tedious to do. We plan on a very good seal coat on the
exterior of the block and have a vapor barrier like finish being provided on the interior. This may do
quite well without any serious moisture absorption worries. Our project starts block work in less than
two weeks; your advice would be appreciated.
A: Most all the expanded perlite producers discontinued making silicone coated material more than 10
years ago. It is no longer required by ASTM C549. You may want to check to be sure the contract is up to
date on its requirements. While the silicone coated product is hydrophobic, it does not affect any of the
insulating properties or do anything that users experienced. Consequently, it only added cost to the
product and no real value. Supplemental drainage would not be recommended. Expanded perlite flows
like water and flows to any open areas. This is why any openings are to be sealed before the perlite is
added. No one wants piles of expanded perlite repeatedly developing near any opening.
Bulletins: Perlite-looseFill-insulation; Thermal-Performance_Perlite-Insulated-Masonry
Q: My name is Kim Stewart and I work with Therm O Rock West. The president of Therm O Rock, Ron
Dobkin, directed me to your offices and they directed me to you. We have been asked by one of our
vermiculite customers to provide a comparison of all of the different sorbents. Obviously, we’d like to
compare perlite and vermiculite, since Therm O Rock West produces both. We would also like to
compare to poly absorbents, dried peat moss, coir, DG, etc. Does either the vermiculite association or
the perlite association have any such info? Can you direct me to another organization that might
provide that info? We’d prefer that the info be provided in a chart and cover absorbency, cost,
chemicals or materials absorbed, safety, etc.
A: Nice to hear from you. We are just about finished with a new bulletin on water holding capability of
various perlites [attached is the last draft of it]. Hopefully, this will help. The second one is for specific
uses of perlite for water quality. I thought it might be of interest to you as well. Both of these are the
latest drafts. A few refinements may yet be made before we post them for everyone. The Perlite
Industry does not have corresponding information on vermiculite.
Bulletins: Perlite-Water-Holding-Capacity-07112018; Perlite-for-Water-Quality- 07.11.2018
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q: I am offering affordable housing solutions to the rural poor in India. Here we offer 30 sq. mtr single
story homes as shown in the attachment. We are looking for a reliable, low-cost terrace coating solution
which can insulate the home. The terrace has lintels hollow blocks and then screening and a 50 mm
concrete layer. Can we mix perlite and eps/fibers in this mix to get a minimum R value of 40? Please
suggest a member of your organization who can assist me in the above designing.
A: Attached are a number of our Perlite Institute bulletins on perlite plasters. However, it is unlikely that
an R value of 40 for the wall could be obtained only with the plaster. I also included one on perlite loose
fill since the wall is hollow. Since you are striving for maximum insulating values, it seems that this
should be considered as well.
Bulletins: Lighweight-Fiber-Reinforced_Perlite-Cement-Plasters; Lightweight-Perlite-Aggregate_Cement-
And-Gypsum-Plasters; PerlitePlaster-draft5-AGK-07.04.18; Thermal-Performance_Perlite-Insulated-
Masonry; Perlite-looseFill-insulation
Q1: I have specification that requires pumice or slag to create a one and three hour fire rated wall. Is
there any perlite made with pumice that would create a one or three hour fire wall?
A1: Attached are a couple of our Perlite Institute bulletins on light weight cement plasters that can be
applied to block walls that yield four hour fire ratings. I have also included our light weight cement
bulletin which illustrates the strength that can be expected from various mixes. Attached is another
bulletin from one of our members who does a great deal of light weight cement applications. It may
provide some additional information that maybe useful to you.
Bulletins: Lightweight-Perlite-Aggregate_cement-And-Gypsum-Plasters; Thermal-Performance_Perlite-
Insulated-Masonry; GulfPerliteConstructionalBrochure
Q2: Let me ask this question, what is the minimum thickness of perlite that can be used in a 8” and 12”
cmu to achieve a three hour wall. Attached document and table 1 is information my engineer supplied
to me, but it does not list perlite. Do you have any literature that supports a minimum thickness of
perlite?
A2: I am not sure what the meaning is of minimum thickness. Expanded block fill flows like water. It fills
up the entire open cavity so the thickness of the perlite bed would be equal to the width of the open
core. The four hour rating was determined according to UL standards. I am not sure what additional
information would be appropriate until I understand the thickness question.
The fire rating for filled block certainly should achieve the targeted one to three hr. rating and then
some. Shown below is information from the Silicone perlite loose fill bulletin – first page near
bottom. Over the years it has been recognized that silicone coated loose fill performs just like uncoated
material from an insulating and fire rating standpoint. Consequently, few expander perlite producers
make any silicone treated material anymore.
Bulletins: Silicone-Perlite_Loose-Fill-Insulation; Perlite-looseFill-insulation
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q1: I'm a general contractor in Ontario Canada. I recently was award a renovation project which
includes removal of textured ceiling or popcorn ceiling as some call it. My concern is this: I haven't been
able to get a direction or clarification if the Perlite in the textured ceiling is asbestos based and if proper
asbestos remediation is necessary, or would proper respiratory masks and dust control would suffice.
The homeowner had it sent to Pro-Lab which is located in Florida. They confirmed Perlite in the
texture. Also a material called binders was also in the lab report. Not sure if this is a by-product of
Perlite. If at all you can help with this dilemma it would be greatly appreciated or if you can direct me in
anywhere to resolve this matter.
A1: You are in luck! Expanded perlite does NOT contain any asbestos at all. It is considered a nuisance
dust. Even so, we recommend that people wear respirators to minimize the exposure to the dust. Perlite
does make one cough. I have attached our bulletin on the health effects of perlite for additional
information for you.
Q2: Thank you very much for the clarification regarding my dilemma. I appreciate your time and I'm sure
the homeowner will as well. We can now move forward with this project.
A2: I am glad we could be of help. Just be sure to have the guys wear respirators or they will be
coughing a lot. My guess is the guys do this normally anyways. I even cough when I go to a perlite plant.
It normally takes a day or so before the sensitivity to the dust subsides.
Bulletin: Health-effects_perlite
Q: I work for engineering and construction company, CDMG/Stevens. We would like to fill the cells of
rather large existing block building. The building is constructed of 12” wide CMU with a bond beam and
roof already installed. Would it be possible to drill holes in the top cells directly below the bond beam
and pneumatically blow in the perlite insulation? If so, do you know of what equipment would be used
for this process? Any other ways of installing the perlite in a retro fit condition that you could suggest
would be greatly appreciated.
A: I am not aware of any such equipment but will talk to some of the Perlite Institute members who
supply this material. I should hear back from them by Tuesday. The problem of blowing perlite is how to
get rid of the air without making the world go dusty. Expanded perlite flows like water. It may be that an
elevating mechanism that allows the perlite to flow down by gravity would do the job. This is why I need
_____________________________________________________________________________________
Perlite Institute Technical Q&A’s June 2018 – August 2018
Q1: We are interested in using perlite insulation for concrete roof application for the Point Fortin
Hospital Project. Our Client is the Government of Trinidad and Tobago.
The area to be insulated is 5,000 square meters and we need to achieve a u-value (British) of 0.48.
We kindly ask for your advice on the following:
The thickness of the insulation using the Perlite required to give the u-value The mixed design of the cement/water/perlite/sand, ratio Application procedures Recommended Supplier (preferably from the USA due to shipping cost). No. of bags required for the complete works (based on the area and the recommended
thickness). And if possible the average cost per bag
A1: I have attached several of our Perlite Institute bulletins concerning roof decks. Normally, people use
a 6:1 ratio for the mix to get the desired strength as well as insulating properties in addition to the
weight for areas with high winds. This includes typical mixes with sand and filler. The lower the U value,
the better the insulation. The bulletin illustrates the impact of various density mixes. The more
perlite, the lower the U value and the better. [I am not aware of anyone who installs less than 2 inches
[5 cm] thickness of light weight cement so I would not recommend going with a thinner coat just for the
U factor. I also included a bulletin on how to mix and transport the mixture since perlite is hollow glass
bubbles and will break with agitation. The Perlite Institute does not sell or supply expanded perlite. It is
a composition of independent members who supply material in their respective areas. Consequently, we
cannot give you any indication as to the pricing of material. This has to be done directly with whomever
you select. Our Perlite Institute web site has a directory on the homepage which hyperlinks to members
in the selected area. You can find member contact information by clicking on the white dots on the map.
My initial thought is that a member that is close to the ports may be able to help you. You would have to
contact them for more information.
Q2: We just have one question, can the perlite mix you suggested (6:1 ratio) be mixed with a water
proofing compound (Nexseal water proofing admixture) as per the attached.
A2: This is the first I have encountered that additive. The description certainly appears to be a good
material. I would recommend you contact the Nexseal supplier and specifically ask them their
recommendations for light weight cement mixes in your environment. Many admixes are for certain
_____________________________________________________________________________________
Q: Per our phone conversation, would you please send us any information or photos re perlite puffer?
A: I have attached a sketch of a typical perlite expander unit to give you an overview of the type of
system is normally used to expand horticultural perlite. Most all users install these inside a building with
the exception being if it is in a warm environment. Changes in the exterior weather can have quite an
impact on the performance of the expanders. Sized ore is normally purchased in 20 or 100 ton quantities
Perlite Institute Technical Q&A’s June 2018 – August 2018
at a time. The ore which is 65 #Ft3 is normally stored in round silos. They have to be large enough to
handle several incoming loads. There are some locations where the ore is stored on cement enclosed
pads from which scoops of ore are then taken to a feeder for metering to the expander. This involves
more labor and mobile equipment. There are two perlite institute members who fabricate entire perlite
expansion units. More information can be obtained at their websites
http://www.inconcorp.com/equip/equip.htmhttp://www.inconcorp.com/equip/equip.htm
http://www.silbrico.com/PerliteEquipment/plantexptech.html
Most horticultural expanders produce about 1 TPH to produce about 325 Ft3/hr. of material at about
6#/Fr3. The expanded perlite is glass bubbles which are friable and care needs to be taken in
transporting them to the use point. Any producers screen the expanded product to control the particle
size of the desired product. This obviously results in the generation of unwanted by-product that has to
be dealt with as well.
Things get a lot more complex the further one gets into a project so feel free to contact me.
Bulletins: Typical Perlite expander system (excel doc); Perlite-GradesSizes
Q1: I am from the country of Georgia. I am going to build house and have two questions about building
materials.
1. Do you recommend building a house with Perlite block, or is it better to use perlite only for loose
fill insulation?
2. Do you think it will have an insulation effect if I fill pumice block holes with perlite?
A1: I have attached a few of our Perlite Institute bulletins on light weight blocks and insulation of those
blocks. The light weight blocks made with perlite filler provide better insulation than heavy density
blocks. The key is how much strength is needed, which should determine the density of the blocks. The
next issue is block size. Larger blocks have greater insulating properties than the smaller ones. In
response to your second question, my guess would be that a pumice block would be denser than a light
weight block of the same size made with perlite. From an insulating standpoint I would say the lighter
the block the better. Of course, this does NOT take into account economics which are different for every
area.
Q2: Two more questions…
1. I am going to use Blocks on frame construction and because of this Perlite block strength is absolutely
enough for now. However, I am concerned about what will happen after 15-20 years. Do you think
Perlite block life expectancy will be similar as common concrete or pumice blocks?
Perlite Institute Technical Q&A’s June 2018 – August 2018
2. Do you think Perlite blocks are as reliable as ordinary concrete blocks during earthquakes?
A2: I have never encountered any issue relative to the durability of cement blocks so it is unlikely that in
15-20 years there will be any issue with the LWD blocks. As to earthquakes, that is normally an issue for
the local area relative to what could happen. Each area has their own criteria for their areas so that is
something you will need to check with your local authorities. I would suggest that one would need to
strategically locate rebar in both the vertical and horizontal areas to protect for earthquake
activity. Again, this is a suggestion and this matter is something that should be discussed with your local
authorities.
Q1: I am developing a blanket cement based plaster for applications in Australia to increase thermal
barrier on external walls. My perlite percentage is 20 percent of the formula with application 10mm.
Would you have any support information to assist my development? Can you help me my 1:5 cement to
perlite by volume 15 mm thick wall plaster is not giving me enough R value?
A1: I have attached our PI bulletin on perlite/cement mixes which shows the expected R value for such
mixes when they are 1” thick, about twice what you have applied.
I also attached our Perlite / cement plaster mixes that are used for coating block and steel. Several
coatings are normally used. The data on these is directed primarily on the fire rating that results and not
the insulation. I do not know what R rating was expected, so I cannot really comment on what you
obtained verses what was expected.
Q2: I can’t find the R Values in your P1 Bulletin on Perlite Plaster, please advise.
A2: I figured out why you could not find the R values on the plaster bulletin - they are not there! The
majority of the effort with plasters is their impact on fire rating. The Light Weight Perlite Cement
bulletin shows the K value for various formulations. The inverse of K is the R factor for 1 inch thick
coverage. So, the K factor of a 1:5 ratio of cement is 0.71. The inverse of this for the R rating for 1 inch
of coverage is 1.41 R. Since you have a 155 mm thickness, that is equivalent to .61 of an inch which then
translates to an R factor of 0.86.
Q3: Can you give me the metric value of your 15 mm R value on 5:1 formulation
A3: The K factor for a 5:1 ration is a unit of insulating value is 0.71 for 1 inch [25,4 mm] thickness. This
equates to a 1.408 R factor for 1 inch thickness. Since 15 mm thickness is 0.59 percent of an inch, the R
factor would be reduce by this amount yielding a R factor is 0.8 .
Bulletins: Perlite-Concrete; Lightweight-Perlite-Aggregate_Cement-And-Gypsum-Plasters; Thermal-
Performance_perlite-Insulated-Masonry
Q: I have read with interest your article titled "Perlite for Non-Evacuated Cryogenic and Low
Temperature Service" regarding the physical character of expanded Perlite:
Perlite Institute Technical Q&A’s June 2018 – August 2018
In relation to the same, I would be grateful for any clarification you can provide on the below queries
regarding cryogenic Perlite:
a. Bearing in mind its size, would cryogenic perlite get caught in a mesh of 0.84mm diameter if the perlite was suspended in liquid cargo (LNG) which was being pumped through that mesh at a significant rate (for example 10,000m3/hr) (and afterwards flushed through by 5,000m3 of cargo without any perlite suspended within it)?
b. Could perlite float on convection currents (i.e. in a gaseous environment), and if so, would it be able to reach a height of 30m?
A: A- It is unlikely that perlite would be suspended in the LNG to start with. Only about 10 percent of the
expanded cryogenic perlite is larger than the 0.84 mm [20 mesh] size of the mesh being used. I would
suspect that if there was any perlite in the LNG, only a small portion would be caught by the
screen. Furthermore, it could easily be broken down by the pressure involved in pumping through the
screen. You did not mention the pressure involved in the pumping. That information would help. After
that, I can check with some of our Perlite Institute members who regularly work in the cryogenic area
just to be sure.
B- Expanded cryogenic perlite is 2.5 to 5 Pounds/ft3. It should not float in a gaseous environment. I
certainly have never heard of that happening.
Q: I am a Research Engineer with Saint-Gobain Corporation and am currently leading a project to
improve our expanded perlite quality. I have several questions about equipment design and best
practices and I was hoping to be able to discuss them with you. Please let me know if you would be
willing to work with me on this and hopefully we can schedule a phone call.
A: Every system is unique as well as the application. There is no “right” way to expand perlite, just a
variety of ways. There are some basics which hopefully, can help you with which is why it is good for us
to talk.
Here are a few of the things we will be covering in our phone call this afternoon:
What is the expanded product being used for The ore grade being used The target density The production rate The type of furnace being used The draft on the system An estimate of the fuel per hour or ton An estimate of the air / fuel ratio
Q: We would like to know the exact density and water holding capacity of our perlite in addition to
other tests. I am having a hard time finding a lab that will run these tests.
A: It is rare that any perlite producer will ever use an outside lab since most all testing is done by them. Consequently, I am not aware of any such facilities. The Perlite Institute is currently developing
Perlite Institute Technical Q&A’s June 2018 – August 2018
information on water holding capacity of expanded perlite. Normally it ranges from three to eight times the weight of the expanded perlite. The perlite’s water holding capacity is dependent on the ore source, the size, density, and fractional density of the expanded perlite. We expect to have a bulletin on this in the near future. I will have to make a note to send you that as soon as it is available.
As to density testing, listed below is our Perlite Institute test method for this that most everyone uses. Note: loose weight density is much different than the packed density of the product. The type of packer has a great deal of impact on how much air is entrained in the product so bag size is NOT an indicator of the effective loose weight density.
LOOSE WEIGHT DETERMINATION OF EXPANDED PERLITE PI Designation: 200- 77 SCOPE This method covers the determination of loose weight density of expanded perlite. SIGNIFICANCE OF TEST The density to which a perlite ore is expanded controls many of its properties. It is important to be able to measure this density as a control method. APPARATUS (a) Shovel or scoop. (b) Measure of known capacity, between 1 and 2 liters. (c) Balance or scale sensitive to within 0.1 percent of sample weight to be tested. PROCEDURE (a) The measure shall be filled to overflowing by means of a shovel or scoop, the perlite being discharged from a height of not to exceed 50 mm above the top of the measure. Care shall be taken to prevent, so far as possible, segregation of the particle sizes in the sample. (b) The surface of the perlite shall then be leveled off with a straight edge. (c) The net weight of the perlite in the measure shall be determined. CALCULATIONS The loose weight in kilograms per cubic meter is determined as equal to: Weight of perlite sample in grams/Volume of perlite sample in milliliters*1000 The loose weight in pounds per cubic foot is determined as equal to: Weight of perlite sample in grams/Volume of perlite sample in milliliters*62.4
Q2: Thank you so much for your response. I appreciate the information about performing the bulk
density (loose weight) test. I am still curious of where you got all the information on your website for
such things as Specific Gravity, Refractive Index, Ph., Free Moisture, and all of the "Typical Elemental
Analysis.” Yes, I would be really interested in the developing information on water holding capacity of
expanded perlite. Just curious of how you know that the water holding capacity ranges from three to
eight but don't have a test for it? I have ran my own version of "water holding" capacity but would like
to know the actual test so we can compare apples to apples. I have spoken to several labs and none of
them will run this test on perlite because they don't know what the test is. We would love to join the
Perlite Institute in the future but would like to see more info that shows how the data was obtained.
A2: The following is a list of the standard Perlite Institute test methods which is being revised.
CONTENTS Page
PI 108-77 Method for Bulk Box Car Sampling of Sized Perlite Ore… … … … …
PI 109-77 Method for Sampling Sized Perlite Ore From Hopper Cars… … … …
PI 110-77 Sampling Perlite… … … … … … … … … … … … … … … … …
Perlite Institute Technical Q&A’s June 2018 – August 2018
PI 111-77 Preparation of Perlite Sample for Testing By Coning and Quartering
Method… … …
PI 112-77 Preparation of Perlite Sample for Testing by Splitter or Riffle Method
PI 113-77 Sieve Analysis of Fine Materials… … …
PI 114-77 Sieve Analysis of Expanded Perlite Volume Basis… … … … … … ..
PI 115-77 Sieve Analysis of Expanded Perlite Weight Basis… … … … … … ...
PI 116-77 Fractional Density of Expanded Perlite..
PI 117-77 Wet Screen Analysis… … … … … … … ...
PI 118-77 Determination of Free and Combined Moisture in Perlite…… … … ..
PI 200-77 Loose Weight Determination of Expanded Perlite… … … … … … ..
PI 201-77 Compacted Density… … … … … … … … .
PI 300-77 Determination of "Floats" and "Sinks" in Expanded Perlite… … … .
PI 301-80 Percent Nonexpansibles in Perlite… … ..
PI 303-77 Water Repel1ency Test… … … … … … ...
PI 305-77 Yield Test for Perlite Aggregate… … … .
PI 306-80 Compaction Resistance Test… … … … ...
PI 307-77 Perlite Ore Expansibility Test… … … …
PI 400-77 Setting Time of Gypsum Plaster… … …
PI 401-77 Plaster Coverage Test… … … … … … …
PI 501-83 Method for Determination of Wet Density
And Relative Water Permeability of Powder Type Filter Aids… … … … … …
ASTM Specifications…………………………………………………………..
CEN Specifications……………………………………………………………..
We are still in the midst of developing test methods for the amount of water that various sized
expanded perlites from various ore deposits can hold. Until we have completed that, we should not
make a “tentative” test method available to any users. I will make a note to send you a copy when that
is complete.
Q: I have a 100 year old house with planks on the interior walls and clapboard on the exterior walls. I hesitate putting blown in insulation like fiberglass, rock wool or cellulose because there's no vapor barrier. The house in in hot Central Texas near Austin, so I do want insulation and was wondering what you thought of using Siliconized perlite? Also, if it is a good idea, is there a blower to put it in the walls stud cavities? I would take the top plank off for access.
A: A silicone coated perlite is not needed for this type application. It simply makes the material
hydrophobic which is not needed in such an application and is more costly. I have attached our bulletin
on block fill which illustrates the insulation capability of perlite at various thicknesses. The expanded
perlite for insulation pours like water. Therefore, it is mandatory to seal any cracks or it will simply flow
out. This includes the electrical outlet boxes. The expanded perlite is considered a nuisance dust but
Perlite Institute Technical Q&A’s June 2018 – August 2018
makes one cough. It is standard practice even in the production facilities to wear respirators. It is normal
for people to pour the perlite from 2.5 or 4 cubic foot bags into the areas. Pneumatic conveying like
done with cellulose does not work. You can find Perlite Institute perlite suppliers in your area by going
to the directory on www.perlite.org.
Bulletin: Perlite-looseFill-insulation
Q: A few of us from the Michigan Technological University Concrete Canoe Team stopped in at Midwest
Perlite, Inc. in Appleton, WI to get some information about perlite for use in our boat next year. One of
the rules we have to follow covers our aggregate blend and requires us to include an ASTM C330
compliant aggregate as at least 25 percent of the aggregate volume in our mixture. We are really
interested in using perlite because of its low density, but need documentation that it has been lab
certified to meet the ASTM C330 requirements. Midwest Perlite told us that if anyone can figure this
out, you're the man to ask, so we were wondering if you have the documentation already or if you knew
of anywhere one could find it. Let me know what you think.
A: The following is from a David Yarbrough from the ASTM. It is his opinion that the ASTM 332 tests
would be more appropriate than the 330 per below:
Incidentally, they also will do lab testing if needed.
I recall providing some perlite for a concrete canoe project at Tennessee Tech several years ago. As far
as I know the project was successful. C330 and C332 are somewhat different. C330 is for structural
concrete. C332 is for insulating concrete. The objective in the case of the canoe project is lightweight
concrete – this would be in the category covered by C332. C332 does not appear to have mechanical
property requirements. A factor with low-density concrete is reduced shear and compressive strengths.
These properties are related to the composition (amount of perlite used). I recall the very low density
(high perlite content) had very low shear resistance (not good for a canoe). My guess is that the
concrete density should be greater than 40 PCF (a guess). The concrete canoe contest is related to
engineering departments (I believe this is still the case). The students should make some candidate
mixtures and test the 28-day compressive strength. I would suggest a need for numbers of at least 250
PSI. Shear strength is more crucial – don’t want the canoe to shear into pieces when lifted. The purpose
of the contest is for the competitors to do some materials research. I would consider some light-weight
reinforcing material – like hollow PVC pipe or tubes also, low density concrete has to be sealed against
water penetration. (obvious, I suppose). In my opinion C 330 is not related to the project.
Q2: Is there a published criterion for maximum amount of moisture content (% scale) for perlite based
roof insulation boards, or alternatively, max content allowed before the board cannot be covered by
roofing materials?
A2: Expanded perlite used in insulating boards does not have an issue with water content. Before sized
perlite is expanded into the bubbles used in board, it has about three percent moisture content. About
two percent is free water and one percent combined water which is bond. The conversion process is at
Perlite Institute Technical Q&A’s June 2018 – August 2018
about 2,000 F so any free water is liberated as is most of the bond water. Consequently, there are no
concerns about its water content. Those who make insulating boards use proprietary processes which
incorporate the perlite with other ingredients. I would suggest that you contact the producer of the
perlite insulating board in question and ask them specifically if there would be any concern about their
material. They should have such information. The Perlite Institute does not have any information due to
the many different formulas that are used in so many different markets. Many incorporate expanded
perlite into their mixes to make light weight cements which can then be used for roof decks. These
obviously include quite a bit of water content in making up the concretes. I have attached a couple of
our Perlite Institute bulletins which illustrate these points.
B: Perlite-Concrete; Perlite-Insulating-Concrete_Roofdeck; Perlite-Insulating-Concrete_Roofdeck-Specs
Q: I am a home owner who is building his own home. I built the floor to be able to have 1 ½ inch of 15
lb. per sq. ft. (120 lbs. / cubic ft.) lightweight concrete poured over the pex tubing. I have viewed your
organizations web site with regard to the various mixes. The question I have is in regards to the type of
perlite. I live in the Seattle area and most of the perlite in the area is sold for agricultural use, some is
sold by masonry suppliers for insulation between cement blocks. In talking to the masonry supplier they
are unaware of its use in lightweight concrete. Is there a particular grade or type that I should be looking
for?
A: Uncoated masonry fill can be used for making light weight cements [Attached is our bulletin on
perlite grade sizes]. Coated material is hydrophobic and will not wet into cement. It is rare for this to be
used anymore but something to be aware of. Some producers do make a slightly heavier large density
expanded perlite for light weight cements for large jobs such as roof decks. Supreme Perlite is located in
Portland and can be contacted if need be. Their information is located on www.perlite.org. Also
attached is a bulletin on mixing perlite. Perlite, being light weight glass bubbles, will break down with
heavy mixing so one has to be careful of this property
B: Perlite-GradesSizes; Perlite-Concrete; Transit-Mix-perlite