ashrae standard 62.1 update

© 2008 Trane

ASHRAE Std 62.1 UpdateWhere Are We Now?ASHRAE Std 62.1 UpdateWhere Are We Now?

May 2008

Dennis A. StankeTrane • La Crosse, WI

© 2008 Trane

ASHRAE Standard 62.1

What Is It?

Title: “Ventilation for Acceptable Indoor Air Quality”

Purpose: “… to specify minimum ventilation rates and indoor air quality that will be acceptable to human occupants and are intended to minimize … adverse health effects.”

Scope: All commercial, institutional, and high-rise residential buildings

It’s the ventilation standard …

© 2008 Trane


Why Care?

It’s the basis for many ventilation codes, both now (UMC) and in the future (IMC)

More stringent than codes in some cases (helps establish the “standard-of-care”)

Less stringent than codes in some cases (helps designer in pursue code variance)

Compliance with Std 62.1-2004 is a prerequisite for any LEED-NC credits (Sections 4 thru 7 – except Section 6.3 – or the building code)

© 2008 Trane


What’s Its History?

62-2001a little more change

62-1999a little change

62-1989higher rates

62-1973first issued

62-1981lower rates

1990 2000 20101970 1980

62.1-2004new VRP, many lower rates

2006 SupplementETS separation

62.1-2007 corrections, clarifications

© 2008 Trane

what does Std 62.1 require now?

Must Comply With …

General requirements (Sect 4 and 5) To reduce generation of indoor contaminants and introduction of

outdoor contaminants

Ventilation requirements (Sect 6) To dilute and remove indoor contaminants

Construction, startup, operation and maintenance requirements (Sect 7 and 8) To assure installation/operation as designed

© 2008 Trane

Std 62.1-2007 Section 5 Systems and Equipment

5.1 Natural Ventilation. May use natural ventilation in lieu of or in conjunction with mechanical ventilation, provided Perimeter areas are within 25 ft of outdoor opening, which is

least 4% of floor area

Interior areas are within 25 ft of opening, and opening to perimeter area is at least 8% of floor area, not less than 25 ft2

[For mixed-mode buildings, the mechanical ventilation system must comply with Section 6.0, and, presumably, the natural ventilation system must comply with Section 5.1.]

architect

Future: Needs attention, especially mixed mode and hi-rise residential

© 2008 Trane


5.6 Outdoor Air Intakes. Reduce contamination from outdoors Locate intake a minimum distance from outdoor sources, per

Table 5.2. Examples of more than 10 sources/distances: Loading dock 25 ft Dumpster 15 ft Surface below intake 1 ft Cooling tower exhaust 25 ft

Design to limit rain water penetration (using hood, e.g.) or manage water that penetrates

Use bird screens, prevent bird nesting at intake

architect

Future: Working on

Addendum to improve

clarity, add some sources

© 2008 Trane


5.9 Particulate Matter Removal. Reduce rate of dirt accumulation on HVAC devices Use at least a MERV 6 filter upstream of dehumidifying coils

and other wet-surface devices (about 20% Dust Spot)

© 2008 Trane


5.10 Dehumidification Systems. Design to reduce dampness in buildings during mechanical cooling Limit RH to 65% or less at design dew point condition without

solar load [Basic CV systems might not comply] [System configured and controlled properly can comply]

Design so that intake airflow exceeds exhaust airflow [Direct control of building pressure can be used to meet this]

2007: Clarified RH limit at design dew point

© 2008 Trane


5.18 Requirements for Buildings Containing ETS Areas and ETS-Free Areas. Reduce level of ETS in ETS-free areas Classify each area as ETS or ETS-free

Pressurize ETS-free areas with respect to ETS areas

Separate ETS/ETS-free areas with walls, doors

Maintain transfer airflow paths

Don’t recirculate from ETS to ETS-free at air handler

Exhaust from ETS areas

Signage: “This area may contain ETS”

architect

2007: Added Section 5.18: ETS/ETS-free separation

requirements

© 2008 Trane

what does Std 62.1 require?






© 2008 Trane

Std 62.1-2007 Section 6.0

Procedures

6.1 General. For mechanically ventilated systems, find minimum OA intake using either the VRP or the IAQP 6.1.1 Ventilation Rate Procedure (VRP). Prescribes

procedures and outdoor air rates, assuming typical space contaminant sources and source strengths

6.1.2 IAQ Procedure (IAQP). Requires analysis of contaminant sources, concentration targets and perceived air quality targets and calculation of outdoor air rates needed to assure IAQ-performance specified

Compliance with Standard 62.1 using the IAQ procedure does NOT meet LEED NC

EQp1

© 2008 Trane

6.2 Ventilation Rate Procedure. Prescribes zone outdoor air rates & system minimum intake calculation procedures

6.2.1 Air Treatment. If outdoor air is judged to be unacceptable per Section 4.1 assessment: Use MERV 6 filter in PM10 non-attainment regions

Use 40% efficient ozone filter in O3 non-attainment regions with very high peak ozone (160 ppm or higher)

Document design assumptions in all non-attainment regions

Std 62.1-2007 Section 6.2 Ventilation Rate Procedure

Ozone filtration is required for LEED-NC projects in some regions of country

© 2008 Trane

non-attainment areas

PM 10 (size ≤ 10 microns)

US EPA AQS DatabaseJanuary 17, 2007

6.2.1 OA Treatment: Need MERV 6 filter

© 2008 Trane

non-attainment areas (future)

PM 2.5 (size ≤ 2.5 microns)


Future: Addendum 62.1c would require

MERV 11 in many locations

© 2008 Trane

non-attainment areas

Ozone (8-hour)


Fresno, Riverside, Long BeachFresno, Riverside, Long Beach

6.2.1 OA Treatment:Need 40% air cleaner where 1-hour peak exceeds 160 ppb

© 2008 Trane

non-attainment areas (future)

Ozone (8-hour)


Future: Addendum 62.1c require 40%

air cleaners in many more locations

© 2008 Trane

Std 62.1-2007 Section 6.2 VRP – Zone Calculaitons

6.2.2 Zone Calculations. To assure prescribed breathing-zone dilution-ventilation with outdoor air: Use Table 6.1 rates (both cfm/person and cfm/sf) to find

breathing zone outdoor airflow:

Vbz = Rp*Pz + Ra*Az

Use Table 6.2 defaults to find zone air distribution effectiveness, Ez (typically 1.0 in cooling, 0.8 in heating)

Use Equation 6-2 to find zone outdoor airflow for each zone:

Voz = Vbz/Ez

© 2008 Trane

ventilation rate procedure Minimum Ventilation Rates

Table 6-1: Minimum breathing-zone rates for 63 categories

Office 20 0.0 5.0 0.06

Classroom (ages 5-8) 15 0.0 10.0 0.12

Lecture classroom 15 0.0 7.5 0.06

Retail sales 0 0.3 7.5 0.12

Auditorium 15 0.0 5.0 0.06

Std 62-2001 Std 62.1-2007

Rp Ra Rp RaOccupancy category cfm/p cfm/ft² cfm/p cfm/ft²

Prescribes both per-person and per-area rates

© 2008 Trane

Office (5p) 100 20.0 85 17.0

Classroom (ages 5-8) (25p) 375 15.0 370 15.0

Lecture classroom (65p) 975 15.0 550 8.5

Retail sales (20p) 300 15.0 270 14.0

Auditorium (150p) 2250 15.0 810 5.4

Occupancy category(default density/1000 ft²)

Std 62-2001

Vbzcfm

Effectivecfm/p

ventilation rate procedure

Effective Minimum Rates

Std 62.1-2007

70% of OA rates drop; 30% stay same or rise

Comparison of breathing-zone OA flow

Vbzcfm

Effectivecfm/p

© 2008 Trane

Daycare sickroom (25p) 10 0.18 430 17.2

Univ/Col laboratory (25p) 10 0.18 430 17.2

Central laundry rm (10p) 5 0.12 170 17.0

Res dwelling unit (5p) 5 0.06 85 17.0

Res corridor (--) 0 0.06 60 NA

Occupancy category(default density/1000 ft²)

Std 62.1-2007

Vbzcfm

Effectivecfm/p

ventilation rate procedure

Effective Minimum Rates

Check Standard for complete list of rates

New rates and breathing-zone OA flow

Rpcfm/p

Racfm/ft2

2007: Added some occupancy

categories/rates, for example …

© 2008 Trane

6.2.3 Single-Zone Systems. To assure proper intake airflow for system with one air handler per zone: Find system-level outdoor air intake flow:

Vot = Voz

6.2.4 100% Outdoor Air Systems. Assure proper intake airflow for system with one air handler supplying only outdoor air to many zones. Find system-level outdoor air intake flow:

Vot = Voz

Std 62.1-2007 Section 6.2 VRP – System Calculations

© 2008 Trane

6.2.5 Multiple-Zone Recirculating Systems. Intake airflow for system with one AHU supplying mixed air to many zones: Find outdoor air intake flow (Vot) using prescribed equations and procedure to

account for system ventilation efficiency (Ev):

Vot = Vou/Ev … outdoor air intake flow

Vou = D* Rp*Pz + Ra*Az … OA used in zones

D = Ps/ Pz … population diversity factor

Ev = min(Evz) … system ventilation efficiency

Evz = 1 + Xs – Zd … (Appendix A)

Xs = Vou/Vps … average OA fraction

Zd = Voz/Vdz … zone discharge OA fraction


© 2008 Trane

6.2.5 Multiple-Zone Recirculating Systems. Intake airflow for system with one AHU supplying mixed air to many zones: Find outdoor air intake flow (Vot) using prescribed equations and procedure to

account for system ventilation efficiency (Ev):

Vot = Vou/Ev … outdoor air intake flow

Vou = D* Rp*Pz + Ra*Az … OA used in zones

D = Ps/ Pz … population diversity factor

Ev = min(Evz) … system ventilation efficiency

Evz = 1 + Xs – Zd … (Appendix A)

Xs = Vou/Vps … average OA fraction

Zd = Voz/Vdz … zone discharge OA fraction


Incidentally, Vdz = minimum expected

discharge airflow … which might seem to conflict with

Std 90.1 reheat airflow restrictions, but

Exception a5 in Std 90.1 can help resolve it.

© 2008 Trane


Ventilation System Example

Do we have time for an example? No

But, I found total OA intake for a 6-zone school, using different systems and methods:

One RTU per zone (six single-zone systems), both in cooling and heating

One FC per zone, and a 100% OA system, with both CV and VAV ventilation airflow

A reheat VAV (single-path multiple-zone) system using both default Ev and calculated Ev

A series fan-powered VAV (dual-path multiple-zone) system using calculated Ev

© 2008 Trane

VRP 6-zone school example

OA Intake Flow Summary

Ventilation System OA IntakeVot

Single-Zone Clg 8,900

Single-Zone Htg 11,100

100% OA – CV 8,900

100% OA – VAV 8,900

VAV Default Ev 10,800

VAV Calculated Ev 8,400

Series FP VAV 7,800

No population diversity credit

Penalty for “too warm” htg air



Conservatively low default Ev value

Equations for more accurate Ev

Two ventilation paths, highest Ev

© 2008 Trane

VRP 6-zone school example

OA Intake Flow SummaryVentilation System OA Intake

(2001 Vot)OA Intake(2007 Vot)

%Chg

Single-Zone Clg 12,600 8,900 -29

Single-Zone Htg 15,800 11,100 -30

100% OA – CV 12,600 8,900 -29

100% OA – VAV 12,600 8,900 -29

MZS-VAV Default Ev 10,900 10,800 -1

MZS-VAV Calc Ev 10,900 8,400 -23

MZS-VAV Series FP 10,900 7,800 -28

© 2008 Trane

6.2.7 Dynamic Reset. To assure outdoor airflow meets requirement for ventilation load, without over-ventilating: May (optional) reset zone minimum OA flow based on

variations in occupancy (DCV)

May (optional) reset OA intake flow based on variations in efficiency (ventilation reset control)

May (optional) reset VAV zone minimum airflow based on variations in actual intake airflow (economizer)


This Section includes operating control options, not minimum design

requirements.

© 2008 Trane

operation for varying conditions

Zone-Level DCV Approaches

TOD: Determine Voz using effective population, Pz’, based on time-of-day schedule

OCC: Determine Voz using Pz’ equal to design or zero population, based on occupancy sensors

CNT: Determine Voz using Pz’ equal to actual population, based on direct count

Voz = (Rp*Pz’ + Ra*Az)/Ez

(Cr – Co) = k*m*Pz/Vbz = 8400*1.25*Pz/Vbz

= 10,500*Pz/Vbz

CO2: Use differential CO2 to maintain current Vbz = > Vbz-req for current population, based on:

© 2008 Trane

zone-level CO2-based DCV (Users Manual)

Modulate Vbz CO2

10 20

200

400

600

800

1000

zone population, Pz

bre

ath

ing

zon

e O

A,

Vb

z

30 40 50 60

diff

ere

ntia

l CO

2 , pp

m

200

400

600

800

1000

1200

00 0

1200

First, find max and min values for CO2

Vbz-min = 60 cfmC-min = 0 ppm

Vbz-des = 548 cfmC-max = k*m*Pz/Vbz= 10,500*65/548= 1240 ppm

Vbz = 7.5 × Pz + 0.060 × Az

© 2008 Trane

C (CO2, ppm)

Vbz(cfm)

60

548

0 1240

Vbz = 0.3

93 × C

+ 60

The Controller


Modulate Vbz CO2Second, define the proportional Controller

© 2008 Trane


Modulate Vbz CO2

10 20

200

400

600

800

1000

zone population, Pz

bre

ath

ing

zon

e O

A,

Vb

z

30 40 50 60

diff

ere

ntia

l CO

2 , pp

m

200

400

600

800

1000

1200

00 0

1200

Controller adjusts Vbz in direct proportion to sensed CO2

Optional CO2 DCV can save operating energyOptional CO2 DCV can save operating energy

For single zone systems, For single zone systems,

Vbz => min Vbz req’dVbz => min Vbz req’d

To analyze Controller operation: …1. Assume initial C-int, find: Vbz = 0.393*C-int + 602. Given Pz and Vbz, find: C = Pz*k*m/Vbz3. Repeat until C-int = C

© 2008 Trane

6.2.7 Dynamic Reset. To assure outdoor airflow meets requirement for ventilation load, without over-ventilating: May (optional) reset zone minimum OA flow based on

variations in occupancy (DCV)

May (optional) reset OA intake flow based on variations in efficiency (ventilation reset control)

May (optional) reset VAV zone minimum airflow based on variations in actual intake airflow (economizer)


This Section includes operating control options, not minimum design

requirements.

© 2008 Trane

VAV ventilation reset control (no DCV)

Single-Duct VAV System

100% system load (20,200 cfm)

VRC only: low D, constant Vou, reduces Vot

8, 810

© 2005 American Standard Inc.

Votw/ventreset

disc airflow Vdz 4,000 4,100 4,200 4,300 300 1,300vent rate Voz 1,880 1,880 2,190 2,190 85 680vent fraction Zdz 0.470 0.459 0.521 0. 509 0.283 0.585Vou = 6,500Xs = Vou/Vps = 6,500/18,200 = 0.357Ev = 1 + 0.357 – 0.585 = 0.772Vot = Vou/Ev = 6,500/0.772 = 8,410

90% system load (18,200 cfm)8,810

Votreq’d

@ design

8,810

8,410

disc airflow Vdz 5,000 5,400 4,000 4,000 500 1,300vent rate Voz 1,880 1,880 2,190 2,190 85 760vent fraction Zdz 0.376 0.351 0.548 0.548 0.170 0.585

Vou = D*Rp*Pz + Ra*Az = 0.65*7,130 + 1860 = 6,500Xs = Vou/Vps = 6,500/20,200 = 0.322Ev = 1 + 0.322 – 0.585 = 0.738Vot = Vou/Ev = 6,500/0.738 = 8,810

© 2008 Trane

OA

RA

SA

central station air handlerwith controls

communicatingBAS

• Reset outdoor airflow(TRAQ™ damper)

For Vent Reset: DDC/VAV, a BAS, OA flow sensor

DDC/VAV terminals• Req’d ventilation (Vbz, Voz)• Actual discharge flow (Vdz)• Current ventilation fraction

(Zd = Voz/Vpz)

• Totals (Vou, Vps)• “Used” OA fraction (Xs)• Sys vent efficiency (Ev)• New OA setpoint (Vot)

VAV ventilation reset


© 2005 American Standard Inc.

© 2008 Trane

VAV ventilation reset control (with DCV zones)


disc airflow Vdz 5,000 5,400 4,000 4,000 500 1,300vent rate Voz 1,880 1,880 2,190 2,190 85 760vent fraction Zdz 0.376 0.351 0.548 0.548 0.170 0.585

Vou = D*Rp*Pz + Ra*Az = 0.65*7,130 + 1860 = 6,500Xs = Vou/Vps = 6,500/20,200 = 0.332Ev = 1 + 0.332 – 0.585 = 0.738Vot = Vou/Ev = 6,500/0.738 = 8,810

100%

VRC w/zone-level DCV reduces Vot even more © 2005 American Standard Inc.

8,810

Votw/vent& DCV

8,810

8,410

CO2 OCC

260140 140 260 5 40

7,040

Votw/ventreset

Pz

90% 260140 140 ?? 5 0Pz’disc airflow Vdz 4,000 4,100 4,200 4,300 300 1,300vent rate Voz 1,880 1,880 2,190 2,190 85 680vent fraction Zdz 0.470 0.459 0.146 0. 509 0.283 0.431

3600.277

9150.218

Sense CO2, find new Voz

Sensemotion

Vou = D*(NONRp*Pz-des) + NON(Ra*Az) + DCV-NON-CO2(Rp*Pz-est + Ra*Az) + CO2(Vbz-est) = 0.65*(4,780) + 1260 + 0 + 360 + 915 = 5,640Xs = Vou/Vps = 5,640/18,200 = 0.310Ev = 1 + 0.310 – 0.509 = 0.801Vot = Vou/Ev = 5,640/0.801 = 7,040

© 2008 Trane

Std 62.1-2007 Section 6.2 VRP – DCV and VRC in MZS

In operation we could: Sense CO2 or estimate Pz in one or more zones (DCV) and

determine currently required breathing zone OA (Vbz)

Use current Vbz for DCV zones and solve the MZS equations to find current set point for OA intake (Vot)

Actual OA delivered all zones would always equal or exceed minimum required OA flow (Vbz)

Does this approach work? Yes, but I don’t know how

well … it must be analyzed,a TC 1.4 RTAR is in the works

Future: Working on Addendum 62.1g to strengthen optional DCV requirements

© 2008 Trane

6.2.8 Exhaust Ventilation. To assure minimum removal of local contaminants: Exhaust some zones at rates prescribed in Table 6.4.

Examples of more than 20 zones listed: Art classroom 0.70 cfm/ft2 Beauty and nail salons 0.60 Kitchenettes 0.30 Locker/dressing rooms 0.25 Copy, printing rooms 0.50 Toilet – public 50 (cont.) or 70 (cyc.) cfm/wtr

closet


2007: Added a few, e.g., residential

kitchen exhaust

© 2008 Trane

6.2.9 Ventilation for Smoking Areas. To assure more-than-minimum ventilation for smoking-permitted areas, even though specific rates on are not prescribed: Provide more ventilation and/or air cleaning than

prescribed in Table 6.1 in zones where smoking is allowed

Design to prevent air transfer from smoking-permitted to no-smoking areas (thru doors and openings, for example)

Design to prevent air recirculation from smoking-permitted to no-smoking areas (thru the air handler)


Future: These requirements will

be altered by Addendum 62.1i

© 2008 Trane

6.3.1.1 Contaminant Sources. Must identify contaminants of concern, along with sources and source strengths

6.3.1.2 Contaminant Concentration. Must specify target concentration and exposure time, referencing cognizant authority, for each C of C

6.3.1.3 Perceived IAQ. Must specify target perceived air quality in terms of percent satisfied

6.3.1.4 Design Approaches. Must follow an acceptable design procedure to find required zone and system airflow rates, and other parameters (e.g., air cleaner efficiency)


IAQ Procedure

© 2008 Trane

May be used in lieu of VRP: To take ventilation-credit for low-emitting materials

To take ventilation-credit for air cleaning

To achieve specific target contaminant concentrations or levels of perceived IAQ (percent satisfied)

But … It doesn’t apply when C of C is ETS … there’s no target

concentration from any cognizant authority to reference It doesn’t apply to LEED-NC jobs. EQ prerequisite 1 requires

compliance with the VRP of Std 62.1-2004 It’s not allowed directly by the model codes


IAQ ProcedureFuture: Needs

attention

© 2008 Trane

operating requirements 8.0 Operation & Maintenance

8.2 Operations and Maintenance Manual. Developa building operations and maintenance manual

8.3 Ventilation System Operation. Operate in accordance with Manual

8.4 Ventilation System Maintenance. Maintain in accordance with Manual Building

Operation

Manual

Future: Working on Addendum related

to Std 180

© 2008 Trane

62.1 Update Summary

SSPC 62.1 continues to refine Std 62.1 in response to: Change proposals (both internal and external)

Interpretation requests

Changes within the industry (LEED, building code needs)

Continuous maintenance in action!

© 2008 Trane

What about those Questions on the 2008 Member Ballot?

They relate directly to Std 62.1 and other “IAQ” or ventilation standards

“Dude, check it out. For me they’re just a’ight.” But, I voted YES to all, because they tend to clarify

provisions in the Member Petition of 1999

For example (if we have time) …

© 2008 Trane

Ballot Question 1

Should ASHRAE Standards … contain health-based limits for pollutant concentrations only when those limits have previously been issued by nationally or internationally recognized health authorities, e.g. U.S. EPA, OSHA or WHO, and for which standardized measurement methods exist?

To me, YES means that for ASHRAE standards, I recommend:

Use of health-based limits only for contaminants with established limits and measurement methods, and if the limits are set by health authorities (ASHRAE can’t set health-related limits)

For example, a standard can include a limit for ozone, but not for ETS

© 2008 Trane

Ballot Question 2

Should ASHRAE Standards and Guidelines be allowed to specify means and methods for limiting the concentrations of pollutants normally considered in the design of HVAC systems, even for pollutants that may not have maximum permissible concentration levels set by a recognized health authority or for which standard measurement methods don’t exist?


Allowing methods for limiting contaminants without health-based limits (e.g., fans for toilet exhaust) (ASHRAE can set non-health related contaminant limits)

[For example, a CO2 limit (well below health limits) could be selected and used to control OA flow]

© 2008 Trane

Ballot Question 3

Should ASHRAE Standards … be precluded from requiring measurement of contaminant … or specifying concentration limits that cannot be measured using equipment and procedures in ASHRAE Standard 111 … or using equipment that is common in building ventilation assessment?


No requirements for measurement of or specific limits for concentrations if they can’t be measured using readily accessible measurement equipment (ASHRAE can’t require measurement of hard-to-measure concentrations)

[I almost voted NO, since the IAQP requires target limits that would be hard to measure, but I voted YES because such limits are for design, and need not be sensed for operation]

© 2008 Trane

Ballot Question 5

Should ASHRAE Standards … be permitted to contain factors for use in design calculation, such as mixing efficiencies and air change effectiveness, as long as it is the consensus of the standards writing body that these factors are important to providing acceptable indoor air quality?


That design factors which are important for providing acceptable IAQ be permitted in design calculations, even if they can’t be readily measured in the field (ASHRAE calculations can include hard-to-measure design parameters, if measurement isn’t required)

[Such design factors can be presented as default values, and need not be measured or sensed for operational control]

© 2008 Trane

Ballot Question 4

Should ASHRAE Standards and Guidelines strive to provide health, comfort and/or occupant acceptability consistent with ASHRAE policy?


That ventilation-related goals reflect ASHRAE policy, which indicates that standards meant to protect public health and safety, and to provide occupant comfort and environmental acceptability are appropriate (ASHRAE can write standards with health, comfort and acceptability goals)

[Setting better health, comfort and acceptability as a goal neither claims nor guarantees that such improvements will actually result from compliance – life is complicated]

ashrae standard 62.1 update

Design

ventilation air distribution

ventilation standard

ashrae std

combustion air

local air quality

outdoor air intakes

regional air quality

minimum ventilation