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Current Trends in the Design and Installation of Filtration Systems

Building for HVAC Security

Brian Monk, P.Eng.

Top NewsU.S. Offers Advice on Air Filters for BiodefenseWASHINGTON, D.C. -- U.S. officials issued guidelines on May 2 to help building engineers anddesigners select air filters and cleaning systems to protect people from chemical, biological or radiologicalattacks. The Department of Health and Human Services said the guidelines are meant to help improve airfiltration in buildings such as offices, retail stores, schools, transportation terminals, indoor shopping mallsand sports arenas.

ASHRAE to Host Homeland Security Satellite Broadcast

ATLANTA—Guidance to reduce the threat of terrorism in buildings will be presented as a public service by ASHRAE during an upcoming satellite broadcast on homeland security issues.

Topics will include risk assessment, chemical, biological and radiological (CBR) protection such as envelope tightness,

ventilation systems, particle filtration and gas absorption, pressure relationships and building interior partitioning, and an update on

building codes and standards as they relate to CBR. Through the broadcast, ASHRAE will offer guidance:

•Reduce the threat of terrorism by introducing risk management methods for building protection;

•Educate building owners on the costs vs. the benefits of improved air filtration and the efficacy of currently

available protective measures.

mailto:[email protected]

Building Safety Examined in ASHRAE Technical Program

ASHRAE '04 Winter Meeting ATLANTA -- From smoke control in tall buildings to

release of chemical agents, the HVAC&R industry continues to look for ways to minimize risk for building

occupants during terrorist attacks. Practical applications and case studies related to

building safety will be featured at the American Society of Heating, Refrigerating and Air-Conditioning

Engineers' (ASHRAE) 2004 Winter Meeting technical program. The meeting will be held Jan. 24-28, Anaheim,

Calif.

TRG . BCBR

Technical Research Group Blast, Chemical, Biological

Remediation

Outdoor Air

Filtration Document is a Companion Document

The revised Standard 62-1981, "Ventilation for Acceptable Indoor Air Quality" recommended outdoor air flow rates for smoking-permitted and for smoking-prohibited conditions in most spaces. The 1981 standard also introduced an alternative air quality procedure to permit innovative, energy-conserving ventilation practices. The alternative procedure allowed the engineer to use whatever amount of outdoor air he deemed necessary if he could show that the levels of indoor air contaminants were held below recommended limits.

Key excerpts from ASHRAE Standard 62-99

The revised Standard retains the two procedures for ventilation design, the Ventilation Rate Procedure and the Air Quality Procedure. The goals of achieving acceptable indoor air quality and of minimizing energy consumption appear to imply a compromise. An interdisciplinary committee of engineers, architects, chemists, physiologists, product manufacturers and industry representatives has endeavored to achieve the necessary balance between energy consumption and indoor air quality in this Standard.



The air cleaning used to clean recirculated air should be designed to reduce particulate and, where necessary and feasible, gaseous contaminants. The system shall be capable of providing indoor air equivalent to that obtained using outdoor air at a rate specified in Table 2.

ASHRAE Std. 62 Table 2

CFM/PERSON Conference Rooms 20 Dormitories 15 Offices Office Space 20 Conference Rooms 20 Smoking Lounges 60 Education Classrooms 15 Laboratories 20 Hospitals, Nursing and Convalescent Homes Patient Rooms 25 Operating Rooms 30

Key excerpts from ASHRAE Standard 62-99 (only pertinent sections are shown above).

Emission Trends (1970-1995)

0

10

20

30

40

50

Thousand Short Tons

1970

1980

1986

1988

1990

1992

1994

Particulates

PM-10

Emission Trends (1970-1995)

020406080

100120140160

Thousand Short Tons

1970

1975

1980

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

Nitrogen Oxide

NO

6.1.2 OUTDOOR AIR TREATMENT

If the outdoor air contaminant levels exceed the values given in 6.1.1. (Table 1), the air should be treated to control the offending contaminants.

Air cleaning systems suitable for the particle size encountered should be used. For removal of gases and vapors, appropriate air-cleaning systems should be used.


PROPERLY CLEANED AIR MAY BE RECIRCULATED...

If cleaned, recirculated air is used to reduce the outdoor air flow rate below the values shown in Table 2, the Air Quality Procedure, 6.2, must be used. The air-cleaning system for the recirculated air may be located in the recirculated air or in the mixed outdoor and recirculated airstream.


Air Contaminant Sizes

MOLECULES

HUMAN HAIR

SCAN. ELEC. MICROSCOPE OPT. MICROSCOPE EYE

SMOG

VIRUSES

BACTERIA

POLLEN

TOBACCO SMOKE

FUMES DUSTS

SPORES

Particle Size, microns

10 100 1.0 0.1 0.01 0.001 0.0001

Absorbtive Media

• ACTIVATED CARBON IMPREGNATED WITH PHOSPHORIC

ACTIVATED CARBON IMPREGNATED WITH POTASSIUM HYDROXIDE

• POTASSIUM IMPREGNATED ALUMINA

• COAL BASED ACTIVATED CARBON

Removal Mechanisms

• ADSORPTION

• ABSORPTION

• CHEMISORPTION • CATALYSIS

Properties of a Good Adsorbent

Adsorptive Properties • Substrate Surface Area

(BET N2) • Substrate Carbon

Tetrachloride (CTC Activity)

• Capacity

Physical Properties • Hardness • Bulk Density • Pressure Drop

Pore Structure

• Macropores (r > 25 nm) Used to enter • Mesopores (r = 1-25 nm) Used to transport • Micropores (r < 1 nm) Used to adsorb

Adsorption Isotherm Activated Carbon vs General HC

1.00 ppm 0.50 ppm 0.30 ppm 0.10 ppm 0.05 ppm

100.00

10.00

1.00

0.10

0.01

0.00 1 10 100 1000

Operation Time, days

Cub

ic fe

et o

f MM

-300

at 1

000

CFM

Properties of Sorbent Materials SorbentMaterial

InternalPorosity

(%)

BulkDensity(lb/ft3)

AveragePore

Diameter(nm)

SurfaceArea

(m2/g)

SorptiveCapacity(kg/kg)

AluminasLow-porosity 40 44 7 320 0.20High-porosity 57 53 4-14 250-360 0.25-0.33CarbonsShell-based 60 28-34 2 800-1600 0.40Wood-based 80 16-19 - 800-1800 0.70Coal-Based 60-80 25-37 2-4 900-1200 0.40

Chemisorption

Oxidation Reaction Oxidant + Contaminant + Oxygen Carbon Dioxide + Water

Acid-Base Reaction Acid + Base Salt + Water

Adsorption Wave

Unused Media

Unused Media

Unused Media

Active Media

Active Media

Active Media

Spent Media Spent Media Spent Media

T1 T2 T3

MTZ

MTZ

MTZ

Residence Time, TRS

The superficial amount of time that an air-stream is in contact with the chemical media. Ft3 of Media CFM

x 60 TRS =

FLOW SCHEMATIC THIN BED SYSTEM (TRS L.T. 0.4s)

High Efficiency Particulate Filter

Chemical Filtration Media

ContaminatedAir

Entering

Roughing Pre-Filter

Perforated "V-Shaped"

Media HoldingModules

Clean Air Leaving

FRONT ACCESS FILTRATION SYSTEM

FEATURES • Continuous Filtration • Single or Multi-Pass

Applications • New or Retrofit

Applications • Available For Field

Assembled Banks

AIR PURIFICATION THIN BED RECIRCULATION SYSTEM

FEATURES • Up to Three Stages of Chemical

Filtration for Customized Solutions • High Efficiency Particulate

Filtration • Compact and Easily Integrated in a

Dedicated Space • Horizontal or Vertical Models

UNIVERSAL SIDE ACCESS HOUSING THIN BED RECIRCULATION SYSTEM

FEATURES • High Sealing Integrity • Size Flexibility • Multiple Stages of

Particulate and Gas-Phase Filtration

• Optional Bi-Polar Ionization Section

DEEP BED SCRUBBER (TUBE STYLE)

FEATURES • Dry Scrubbing for

High Contaminant Concentrations

• Reduced Height • Unique Tube-Style

Design

Laboratory Analysis

• Optimize Media Change-Out

• Verify Media Performance

• Respond to Changing Contaminant Loads

Reactivity Monitoring (REMO)

• 99.9% Pure Copper and Silver Strips

• Normalized one-month value for ISA classification (Copper Strip)

• Chlorine and Relative Humidity Analysis (Silver Strip)

Real-time Corrosion Analysis

• Real-Time Corrosion Monitoring

• Constant Surveillance of Critical Environments

• Immediate Indication of Corrosive Potential without Prolonged Exposure Shown: Surveyor, Real-Time Corrosion Monitor

Real-Time versus REMO Data

Time

Cor

rosi

on R

ate

Normalized Corrosion Estimate Real-Time Corrosion Measurement

Point Data Measured by Coupons

Continuous IAQ Monitoring

CASE STUDY New Midfield Concourse Facility, Dulles Int. Airport Outdoor Air Filtration - USAH with Bi-Polar Ionization

Location: Washington Dulles International Airport Objective: Outdoor Air Filtration Equipment: USAH with Bi-Polar Ionization System Key Contaminants: NOx SOx HC PM-10

Media Selection: MM-1355

Custom media blend with High Efficiency (95%) particulate filtration and Bi-Polar Ionization.

CASE STUDY B.C. Hydro - High Voltage DC Link, Vancouver Thin Bed System with Custom Media Impregnation

Location: HVDC Station, Vancouver (Canada) Objective: Removing Mercury Vapour Equipment: Thin Bed System with Custom Impregnation Key Contaminant: Hgv


Activated carbon custom impregnated with iodine to remove mercury vapour.

CASE STUDY Smithsonian National Museum of American History Outdoor Air Purification - Thin Bed System

Location: Washington, D.C. (USA) Objective: Protection of the Star Spangled Banner Equipment: USAH •Outdoor air filtration to remove harmful pollutants such as NOx, SOx, O3 and HC

•Universal side access housing units employing MM-3000 and MM-1000 chemical media.

CASE STUDY George Bush Presidential Library & Museum, TX. Gas Phase Filtration for Libraries and Museums

Problem: Preservation of Artifacts/ Documents Solution: Outdoor Air Filtration Equipment: Universal Side Access Housing Unit •Outdoor air filtration to remove harmful pollutants such as NOx, SOx, O3 and HC

•MM-1355 (UL Class I) media, Surveyor+ electronic air quality monitoring system, Tech-Chek media service .

CASE STUDY Harrah’s Casino, Lake Tahoe, NV Thin Bed Air Purification System

Problem: Environmental Tobacco Smoke Solution: Minimize the amount of O.A. required for dillution by Filtration/Recirculation Equipment: APS-1500 • Eliminate both particulate and gaseous components of ETS

• Minimize the effect of second hand smoke on the non-smoker

• Meet the objectives of local codes and regulations

Guidance for Filtration and Air-Cleaning Systems to Protect Building Environments

from Airborne Chemical, Biological, or Radiological Attacks

Department of Health and Human Services Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health April 2003

“A chemical, bilogical, or radiological airborne threat can come from a wartime attack, terrorist attack, or from an industrial accident”

“Industrial accidents: To provide collective protection for a facility…closing the O.A. intakes during a release, or protecting the air intakes with a filtration system is required”.

“Terrorist Threat: For facilities that require continuous operation during a short duration with little or no warning, such as a terrorist attack, continuous filtration of the ventilation air intakes is required.”

Key excerpts from: Design of Collective Protection Shelters to Resist Chemical, Biological, and Radiological Agents (U.S. Army Corps of Engineers, Feb.1999)

Possible Air Contaminants

Department of Defense USA: Current Problems: Tabun (GA) Anthrax Distilled Mustard (HD) *1 to 5 microns mean particle diameter. Soman (GD) LewIsite (Arsine) *approximately 2500 spores inhaled to cause infection. Lethal Nerve Agent (VX) Decontaminating Agent DS2

“Class II Filtration with little or no pressurization: This class of protection is applicable to a terrorist attack with little or no warning that produces a short duration small-scale release of agent. Outdoor air intakes will be protected by continuously operating filtration units..”

“The filtration system will be sized for the normal facility air intake requirements and need provide little or no facility overpressure”.

“Toxic-free Area Overpressure: The TFA will be designed for a minimum overpressure goal of 0.02 “wg”. Key excerpts from: Design of Collective Protection Shelters to Resist Chemical, Biological, and Radiological Agents (U.S. Army Corps of Engineers, Feb.1999)

“The HVAC system must be designed, operated, and maintained to provide uncontaminated air to the TFA”

Key excerpts from: Design of Collective Protection Shelters to Resist Chemical, Biological, and Radiological Agents (U.S. Army Corps of Engineers, Feb.1999)

• Infiltration – Building envelope

tightness and ventilation control are critical

• Bypass – Filters should be air tight – Check gaskets and seals – Periodically check

Infiltration & Bypass

Physical Security • Prevent Access to Outdoor Air Intakes.

CASE STUDY E-COMM Center, Vancouver, Canada Emergency Air Purification

Location: Vancouver, Canada Objective: Purify contaminated O.A. Equipment: USAH-406 filtration Bank Key Contaminants: CL2

NH3 Media Selection: MM-9000 / 7000

A custom blend of activated carbon impregnated with KOH.

CASE STUDY

Chem Security ASWTC Alberta Special Waste Treatment Center

Location: Alberta, Canada Objective: Toxic release filtration system Equipment: DAS-Twin-bed (14100 / 17600 CFM) Toxic Contaminants

(PCB, Mercuric Conpounds, etc...) Media : MM-3000 (556 ft3)

Designed to maintain safety room below TLV of stored contaminants.

High speed removal if spill occurs.

CASE STUDY Illinois American Water Works Emergency Chlorine Air Scrubber

Design: Absorb 150 lb CL2 release / 18 ACH Objective: Meet NFPA / ACGIH Equipment: ECS-6000 Key Contaminants: CL2


400 lb / min release rate

7 min. room evacuation

Redundant Blower Assembly

CASE STUDY Y2K Emergency Response Center Government of Canada

Location: Public Works Department, Ottawa, Canada Objective: Outdoor Air Filtration, A/C Equipment: Modular system •Outdoor air filtration to remove harmful pollutants such as NOx, SOx, O3,CO, HC

•MM-1355 (UL Class I) media, Surveyor+ electronic air quality monitoring system, Tech-Chek media service .

CASE STUDY Governor’s Mansion Austin, TX. Location: George W. Bush (residence) Objective: Correct Defficient IAQ Equipment: Dectron Internationale

•Reduced IAQ concerns related to mold / VOC

•Combination system of 3 divisions of Dectron Internationale

CASE STUDY

Emergency 911 Center San Francisco, CA. Objective: Pressurization and Purification Equipment: APS General Atmospheric Contaminants (SOX,,H2S, NOX)

Electrical Generator Atmospheric Contaminants :Diesel Emissions (Particulate / Gas) Media Selection: MM-1955 / 7000

Maintained Below ISA G1 Severity-Level Requires Below 1 PPB on all Gases Present in Class I Facilities

Current Trends in the Design and Installation of Filtration Systems

Building for HVAC Security

Brian Monk, P.Eng.