ASHRAE Safety Code for Mechanical Refrigeration. 49 CFR (e)(1)(i). American Society of Heating, Refrigerating and. NOTE: All documents linked from this page are in sourphocingcardmi.gq PDF-format. Interpretation – June 27, (Refers to the requirements presented in. This standard is under continuous maintenance by a Standing Standard Project Committee (SSPC) for which the Standards Committee has established a.
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The Refrigeration Commissioning Guide for Commercial and Industrial Systems provides guidance to owners and managers of commercial and industrial. Standard , Safety Standard for Refrigeration Systems Standard , Ventilation for Acceptable Indoor Air Quality (PDF is not searchable). Standard (packaged w/ Standard ) -- Safety Standard for Refrigeration Systems and Designation and Classification of Refrigerants (ANSI.
However, without detailed study or along with a re-optimized piping layout, perhaps the total system charge will now be in compliance. Another allowable x would be to use one common ducted evapora- tor to condition the two smallest rooms together, allowing both rooms to be summed for purpose of compliance. In lieu of an in-room console unit, another option is to use an above-ceil- ing evaporator unit ducted to one or more of the smaller rooms, while draw- ing unducted return air through the ceiling cavity.
Therefore, the ceiling Advertisement formerly in this space.
The driving force expelling RA from a ruptured refrigerant pipe may be on the order of psig 3. Ceil- ing-mounted transfer ducts are also suspect, since most com- monly used refrigerants are heavier than air. The Engineer- of-Record must decide whether to rely on undercut doors or transfer openings as a path to compliance.
It is clear that some ASHRAE research would be helpful in better dening how to treat an undercut door or a transfer opening. Finally, this author is anecdotally aware of another approach to refrigerant leak management, one that involves the installa- tion of automatic shutoff valves within the eld refrigerant pip- ing.
In conjunction with refrigerant leak detectors, the intent is to isolate a leak to one piping segment and limit the quantity of refrigerant that can be leaked between valves to a quantity below the RCL.
This approach is not addressed by Standard The only place within Standard 15 that refrigerant leak detec- tors are addressed is within the Machinery Room compliance path, which is not appropriate for occupied space.
Conclusions This article intended simply to remind designers who are ap- plying VRF that careful application of Standard 15 is neces- sary.
Within the bounds of Standard 15, VRF systems can be properly selected, designed, installed, and operated. It may be advantageous to remove small rooms from a VRF system and serve those rooms separately; or use more, smaller, separate VRF system networks in lieu of one larger system, or serve multiple small rooms with one common ducted evaporator.
Routing is also a key consideration, to avoid routing refrigerant piping through smaller enclosed rooms with a lower maximum allowable charge. Operating pressures are relatively high, mak- ing the integrity of all the eld joints critical, so enforce speci- cation language requiring pressure testing of eld piping.
Disclaimer The contents of this article shall not be construed as an of- cial interpretation of Standard While the author of this article is a member of Standing Standards Project Commit- tee SSPC 15, the information presented in the article is the view of the author alone and does not necessarily represent the views of SSPC Originally written in , Standard 15 was created to provide guidance for safety concerns in large refrigeration plants using ammonia and other early refrigerants.
Over time, the scope of the Standard has been expanded to cover most refrigerants and systems, but the technology and features inherent in VRFZ systems has not been addressed. Also, regulatory language was incorporated in the revision and, by adoption, can be made part of local code requirements. This is specific to each jurisdiction, so it is important for the designer to be familiar with local codes and regulations.
Therefore, system designers must refer to Standard 34 when applying Standard 15 safety principles to RA refrigerant.
The overall purpose of ASHRAE Standard 34 is to establish a simple means of referring to common refrigerants It also establishes a uniform system for assigning reference numbers and safety classifications to refrigerants. ATEL includes consideration of mortality, cardiac sensitization, anesthetic or central nervous system effects and other escape impairing effects and permanent injury. Toxicologists considered the elderly and children when determining the RCL values for refrigerants.
No discussion on this in Standard. If system components are located in normally occupied spaces, then they must be evaluated for safety and suitability. Corridors and lobbies especially points of egress - should be evaluated as well since their volume is, by definition, part of the connected spaces volume and the restrictions in the Standard limit refrigeration concentrations in these areas to specified amounts.
In most cases such system components including refrigerant piping do not pose a safety or suitability issue. ASHRAE 15 requires factory testing on all refrigerant containing components; as a result, the likelihood of subsequent failure is remote.
Field fabricated connections also require inspection and evaluation.
Refrigerant Leaks in Occupied Spaces Leaks are not defined in Standard 15, but it generally addresses a catastrophic event where full circuit refrigerant volume is to be considered as available for discharge into the occupied space.
Standard 15 also does not address any time period over which a leak might occur. Even in the unlikely event of a line rupture, the amount of refrigerant in a circuit would require a significant period to escape from the system. The design professional should keep in mind that ASHRAE 15 was primarily developed and written for the catastrophic release of the entire contents of a pressure vessel thru a safety valve of large diameter in a short period of time.
There is a clearly defined relationship between the amount of refrigerant in a system and the volume of the occupied space into which the refrigerant could flow.
According to Standard 15, the volume used to determine the refrigerant quantity limits for refrigerants in 7. Occupied space is not necessarily a single room or area. If a group of rooms or spaces offices, corridors, other spaces off the corridor, etc. These connected spaces could also include louvers or permanent openings to adjacent spaces or to the outside, as in a ventilation source or exhaust, and even undercuts on connecting doors, provided there is forced movement of air Note that RA is heavier than air and would spread along floor surfaces as a free gas.