Engineering Controls and Engineering Controls and Laboratory DesignLaboratory Design

Session 4Laboratory Safety Training

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Types of LaboratoriesTypes of Laboratories

Academic vs. IndustrialResearch vs. InstructionalSimilar functions housed

togeather vs. building for entire departments

Future flexibility, diversity.

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Engineering and Architectural Engineering and Architectural PrincipalsPrincipals

Laboratory buildings present difficult challenges– Very little assignable space (65%)– Energy hog, conditioned air, elec.

needs, services, fire protection life safety issues,

Architects must balance beauty with safety.Engineers must balance conserving energy

with safety.Both must balance users needs and cost

with safety.

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Organizations Regulating Organizations Regulating Laboratory DesignLaboratory Design

Southern Building Code (SBC)Building Officials and Code

Administrators (BOCA)National Fire Protection Assoc

(NFPA)Standard Fire Protection Codes

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Basic life safety design Basic life safety design componentscomponents Labs should be designed to provide at

least one, usually two clear means of egress.

The building should have at least two clearly marked means of egress at opposite ends of the building for occupancies up to 500 persons (3 for 500-1000).

Doors must swing in the direction of the exit travel

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Basic life safety design Basic life safety design componentscomponentsTravel distance must not exceed 200

ft (with no fire suppression, 250 with).1 hour fire rated corridors, stairwells,Storage not permitted in these areas.Self closures on doors.Areas of refuge. ADA compliance issues ramps.

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Basic life safety design Basic life safety design componentscomponents

Emergency power for signs, lights, equipment.

Chemical Storage room requirements – Class I Division 2 requirements

(normally contained flammable liquids).

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Fire Protection SystemsFire Protection Systems

Fire Protection Systems–Sprinkler systems–Co2 systems–Inergen (N2 Ar, Co2)–Dry Chemical systems

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Fire Detection SystemsFire Detection Systems

Automatic and Manual stations are required.

Networked systems.Visual and audible.Fire extinguishers.

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Other Issues/EquipmentOther Issues/Equipment

Backflow prevention on the clean water (potable) side. Contamination can occur during pressure differentials of a piece of tubing in a sink under water flush several toilets and the pressure drops on the dirty side causing a back flow of water.

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Chemical resistant casework, typically epoxy coating.

Flammable storage cabinets.Acid storage cabinets.Glove boxes.Local exhaust ventilation for

equipment, processes.

Other Issues/EquipmentOther Issues/Equipment

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Other Issues/EquipmentOther Issues/Equipment

Biological safety cabinets– Class I-III (glove boxes) partial to

100% exhaust.Emergency eyewashes and safety

showers.– Must tempered and require no more

than 10 sec to reach.

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Other Issues/EquipmentOther Issues/Equipment

Compressed gas storage.Vacuum, air, compressor issues.Waste issues.

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VentilationVentilation

All labs using chemicals require 100% out side air. The number of air changes per hour (ACH) are recommended by various organizations.

Regulated by organizations like ANSI (American National Standards Institute), ASHRAE (American Society Heating Refrigeration, Air Conditioning Engineers), NFPA (National Fire Protection Association), OSHA

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Ventilation Cont.Ventilation Cont.

Because of the requirement for 100% outside air and the number of exhaust point and exhaust volume mechanical systems are one of the largest costs.

Variable air volume systems were designed to minimize these cost.

Constant air volume hood systems with set backs

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Types of Hoods Types of Hoods

Constant Air VAVAuxiliary airRecirculated Air (bad bad bad)

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Constant Air Volume HoodsConstant Air Volume Hoods Known also as bypass hoods Face velocity changes as sash is opened

but total exhaust remains constant. Advantages:

– Simpler to maintain.– Can be manifolded or have individual fans.– With off time set backs can be more efficient

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Constant Air Volume HoodsConstant Air Volume Hoods

Disadvantages– Can be inefficient in smaller labs

with several hoods.

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Variable Air Volume HoodsVariable Air Volume Hoods

Maintain a constant face velocity independent of the size of the sash opening

Tracks room pressurization (to keep room negative) to fume hood exhaust.

Manifolded system, redundant fans. Reduces possibility of reentry into

building.

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Variable Air Volume Hoods Variable Air Volume Hoods Cont.Cont.Potential cost savings by allowing

a reduction of supply air when sash is shut.– Hoods exhaust 1000-1200 cfm– 8-10 ach, at $6-8/cfm of conditioned

air can get very expensive.

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Variable Air Volume Hoods Variable Air Volume Hoods DisadvantagesDisadvantages

Initial cost high.Many control points to track,

potential for malfunction.Difficulty in maintaining

sophisticated controls.When the system goes down the

entire building is not exhausted.

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Auxiliary Air HoodsAuxiliary Air Hoods

Advantages– Unconditioned air is deposited into the hood

at the face. Saves on conditioned make-up air.

Disadvantages– Researcher is either cold or hot while

standing at the hood.– Requires a separate supply system.– Difficult to balance, maintain containment.

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Recirculated Air Fume Recirculated Air Fume HoodsHoodsShould never be used,

recirculates fumes after passing air through a filter.

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Single Hood - Single Hood - Single FanSingle FanCAV SystemCAV System

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Multiple Hood - Single Multiple Hood - Single Fan CAV SystemFan CAV System

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Multiple Hood - Multiple FanMultiple Hood - Multiple FanVAV SystemVAV System

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Minimum hood standardsMinimum hood standards All hoods must be tested to the ANSI//AIHA Z9.5 standard.

Requires a manufacturers test, as installed test and as used test. Minimum face velocity must be be 80-120 fpm, optimum 100 fpm at 18” sash opening.

Flow monitors should be installed on all new hoods with a visual or audible alarm

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Minimum hood standardsMinimum hood standards

ANSI/ASHRAE 110 , smoke visualization and tracer gas tests are recommended to identify hood performance and containment.

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Hood installationHood installation

Fume hoods should be placed in the back corner of the room away from turbulence and diffusers.

Not near the means of exit. Away from windows.

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