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American Standard Inc. 1997

The Trane CompanyLa Crosse, Wisconsin

Refrigeration System

Equipment Room Design

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ANSI/ASHRAE Standards

Standard 34-1992

Number Designation And Safety ClassificationOf Refrigerants

Standard 15-1994

Safety Code For Mechanical Refrigeration

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Number Designation AndSafety Classification Of Refrigerants

Purpose? To establish a

simple means of referring to common refrigerantsinstead of using the chemical name, formula, or tradename.

uniform system for assigning reference numbersand safety classifications to refrigerants.


Standard 34-1992

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ASHRAE Standard 34-1992

Refrigerant Safety Classifications

Group A3

Group A2

Group A1

Group B3

Group B2

Group B1

higher

flammability

lowerflammability

no flamepropagation

lower toxicity higher toxicity

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Refrigerant/Blend Data

Refrigerant Chemical Name OrComposition (% By Weight)

Methane SeriesCFC (or R) 11 Trichlorofluoromethane 75F A1 1.6 4,000CFC (or R) 12 Dichlorodifluoromethane 22F A1 12.0 40,000HCFC (or R) 22 Chlorodifluoromethane 41F A1 9.4 42,000

Ethane Series

CFC (or R) 113 1,1,2Trichlorotrifluoroethane 118F A1 1.9 4,000HCFC (or R) 123 2,2Dichloro1,1,1Trifluoroethane 81F B1 0.4 1,000

HFC (or R) 134a 1,1,1,2Tetrafluoroethane 15F A1 16.0 60,000HFC (or R) 152a 1,1Difluoroethane 13F A2 1.2 7,000

Azeotropes

R500 R12 (73.8) / R152a (26.2) 27F A1 12.0 47,000R502 R22 (48.8) / R115 (51.2) 49F A1 19.0 65,000

NormalBoiling

Point

Safety

Group

Lbs/1000

cu ft

PPMBy

Vol

Refrig Qty PerOccupied Space

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Standard 15-1994

Purpose?

to specify safe design, construction, installation,and operation of refrigerating systems.

Scope?

This code established safeguards for life, limb, health,

and property and prescribes safety standards.

Safety Code ForMechanical Refrigeration

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Standard 15-1994

It applies to

mechanical refrigerating systems andheat pumps used in the occupancies definedin Section 4 and installed subsequently toadoption of this code


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Standard 15-1994

It also applies to

parts or components added after adoptionof this code, or a change to a refrigerant of adifferent number designation after adoption ofthis code


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Standard 15-1994

Finally, it applies to

parts or components replaced afteradoption of this code only if they are notidentical in function


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Standard 15-1994

Provides classification criteria for

Safety group Occupancy type

Refrigerating system probability


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Standard 15-1994





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Safety Group Classification

Standard 34s refrigerant safety classifications

Group A3

Group A2

Group A1

Group B3

Group B2

Group B1

higherflammability

lowerflammability

no flamepropagation

lower toxicity higher toxicity

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Standard 15-1994





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Occupancy Classification

Institutional

Occupants cant readily leave without help

Public assembly

Where large numbers of occupants cant vacate quickly

Residential

Occupants have complete, independent living facilities

Industrial

Occupancy is restricted only to authorized personnel

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Occupancy Classification

Commercial

Occupants transact business, receive personal

services, or purchase food or other goods

Large mercantile

Premises where more than 100 people congregate topurchase personal merchandise

Mixed

Two or more occupancies share the same building

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Standard 15-1994





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Refrigerating System Probability

High Probability

Low Probability

System

Designation

Cooling

Or Heating Source

Air Or Substance

To Be Cooled, Heated

Direct

IndirectOpen Spray

Double IndirectOpen Spray

IndirectClosed

IndirectVented Closed

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Refrigerant Quantity Rules

Public Assembly,Refrigerant System Residential, Commercial,

Group Probability Institutional Large Mercantile Industrial

A1 High 2 1 3Low 4 4 4

A2 High 5 5 3Low 7 7 7

A3 High 9 9 3Low 9 9 7

B1 High 2, 6 1, 6 3Low 4 4 4

B2 High 5, 6 5, 6 3Low 7 7 7

B3 High 9 9 3Low 9 9 7

Applicable Rules By Occupancy Classification

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Public Assembly,Refrigerant System Residential, Commercial,

Group Probability Institutional Large Mercantile Industrial

A1 High 2 1 3Low 4 4 4

A2 High 5 5 3Low 7 7 7

A3 High 9 9 3Low 9 9 7

B1 High 2, 6 1, 6 3Low 4 4 4

B2 High 5, 6 5, 6 3Low 7 7 7

B3 High 9 9 3Low 9 9 7

Applicable Rules By Occupancy Classification

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Rule 4

When the quantity of refrigerant in anysystem exceeds Table 1 amounts, allrefrigerant-containing parts, except piping andthose parts outside the building, shall beinstalled in a machinery room constructed inaccordance with the provisions of 8.13.

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Refrigerant Safety Classifications

Refrigerant Chemical Name OrComposition (% By Weight)

Methane Series

CFC (or R) 11 Trichlorofluoromethane 75F A1 1.6 4,000CFC (or R) 12 Dichlorodifluoromethane 22F A1 12.0 40,000HCFC (or R) 22 Chlorodifluoromethane 41F A1 9.4 42,000

Ethane Series

CFC (or R) 113 1,1,2Trichlorotrifluoroethane 118F A1 1.9 4,000HCFC (or R) 123 2,2Dichloro1,1,1Trifluoroethane 81F B1 0.4 1,000

HFC (or R) 134a 1,1,1,2Tetrafluoroethane 15F A1 16.0 60,000HFC (or R) 152a 1,1Difluoroethane 13F A2 1.2 7,000

Azeotropes

R500 R12 (73.8) / R152a (26.2) 27F A1 12.0 47,000R502 R22 (48.8) / R115 (51.2) 49F A1 19.0 65,000

NormalBoilingPoint

SafetyGroup

lbs/1000cu ft

PPMByVol

Refrig Qty PerOccupied Space

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Ventilation

Refrigeration system placement Doors, passageways and access

Refrigerant monitoring

Open-flame devices Pressure-relief piping

General requirements

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Ventilation

Refrigeration system placement Doors, passageways and access




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equipment room design

Ventilation

Volume requirements for

Natural ventilation Mechanical ventilation

Normal rate

Alarm rate

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Ventilation

Remote machinery room

Occupied

Building

OccupiedBuilding

RefrigerationSystem

Lean-to Or OtherStructure WithNatural Ventilation

More Than20 Feet

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Ventilation

Natural ventilation

For refrigerating systems installed outdoors, morethan 20 ft from [any] building openings

F = G0.5

where:F = free opening area (sq ft)G = mass of refrigerant (lbs)

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Ventilation

Normal-rate mechanical ventilation

Needed whenever the equipment rooms occupied

Requirements:

0.5 cfm per sq ftOR20 cfm per person

Must operate, if necessary for operator comfort, at a volume

that limits the temperature rise (T) to no more than 18F

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Ventilation

Alarm-rate mechanical ventilation

Required to exhaust accumulated refrigerant

Q = 100 G0.5

where:Q = airflow (cu ft per minute)G = mass of refrigerant (lbs)

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Ventilation

Suggested exhaust fan location

Exhaust Fan

6 Feet

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Ventilation

Dual-purposeventilation system

ExhaustAirflow

End View

Plan View

VentilationAirflow

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Ventilation

Refrigeration system placement

Doors, passageways and access




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Refrigeration System Placement

Unobstructed space for inspecting andservicing equipment

Must comply with applicable safety standards andrequirements of the presiding regulatory agency

Clear head room not less than 7.25 ft below

equipment over passageways

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Refrigeration System Placement

Multiple-chiller equipment room layouts

Arrangement BArrangement A

ExhaustFan

RefrigerationSystems

ExhaustFan

ExhaustFan

ExhaustFan



AirInlet

AirInlet

AirInlet

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Ventilation






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Doors, Passageways And Access

Equipment room access limited to authorizedpersonnel

Adequate number and type of doors

No openings to other parts of the building

No shared air-handling systems

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Ventilation






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Refrigerant Monitoring

Detector must

Be appropriately sensitive to the refrigerant(s)in use

Activate alarm and ventilation at TLVTWA

Threshold Limit ValueTime Weighted Average

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Sensor location and placement

Height: 18 inches above the floor Plan

Continuous ventilation: Between the refrigerationsystem and room exhaust

Intermittent ventilation: Close to the refrigerationsystem, between it and the room entrance

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Typical refrigerant monitor installation

Chiller

RefrigerantMonitor

5 Feet

Roof Or Concrete Floor

Mechanical Equipment RoomOccupied Space

Sample-In Tubing

Particle Filter

1218 Inches

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Suggested sensor placement for intermittentventilation

Identifies refrigerant sampling points

Refrigeration Systems

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Typical multichannelscanner application

Identifies refrigerant sampling points

Pit

Refrigerant Monitor

With Multichannel Option

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Ventilation






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Open-Flame Devices

No open flames that use combustion air fromthe machinery room shall be installed where any

refrigerant is used.

Exceptions

Combustion air is ducted from outside and sealed to

prevent refrigerant leakage into the combustionchamber

A refrigerant detector is used to shut down combustionautomatically if a refrigerant leak occurs

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Ventilation






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Pressure-Relief Piping

Suggested refrigerantvent piping

15 Feet AboveGround Level

(Alternate Arrangement)

Exterior Wall

Roof

Purge DischargeVent Line

Rupture Disc

Assembly

Flexible Steel

Connection

Drip Leg(Length As

Needed)

1/4 FL 1/4 NPTDrain Valve

Support this pipe!

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Ventilation






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General Requirements

Signs

Changing, charging and storing refrigerants

Self-contained breathing apparatus

Two required per equipment room

Emergency shutdown procedure

General maintenance

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An American-Standard Company

Documents

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