Trane TRG-TRC011-EN manual Application Considerations

period five

Application Considerations

notes

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◆Combustion air ducted from outside the machinery room

◆Refrigerant vapor detector to shut down combustion process in the event of a refrigerant leak

Figure 66

In general, ASHRAE Standard 15-1994, “Safety Code for Mechanical Refrigeration,” does not apply to absorption water chillers due to Section 2.3, which states:

This code does not apply where water is the primary refrigerant.

Section 8.13.6 of the Standard, however, does affect direct-fired absorption chillers. It states:

No open flames that use combustion air from the machinery room shall be installed where any refrigerant is used … Combustion equipment shall not be installed in the same machinery room with refrigerant-containing equipment except under one of the following conditions:

(a)Combustion air is ducted from outside the machinery room and sealed in such a manner as to prevent any refrigerant leakage from entering the combustion chamber, or

(b)A refrigerant vapor detector is employed to automatically shut down the combustion process in the event of refrigerant leakage.

When halocarbon refrigerants (such as HCFC-123, HCFC-22, HFC-134a, etc.) are present during a combustion process, they can break down into products that are both harmful to humans and corrosive to machinery. The intent of Standard 15 is to avoid both of these hazards by preventing refrigerant exposure to any combustion process. Thus, the use of an open-flame device, such as a boiler or the burner of a direct-fired absorption chiller, in a machinery room is strictly prohibited by this section unless one of the exceptions is employed.

Exception (a) allows combustion air to be ducted to the open-flame device from outside the machinery room in order to prevent air (and refrigerants) present in the machinery room from entering the flame. Alternatively, exception (b) allows

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