IEC/UL 60335-2-40 Standard Annex FF Simulated Refrigerant Leakage Test Chamber Study
According to IEC 60335-2-40:2022, UL 60335-2-40:2022, the volume of the room to be tested during the Annex FF chapter test is specified. The formula is as follows:
V = (15 × mFF)/LFL
where
V is the minimum volume in m3 with a ceiling height not less than 2,2 m;
mFF is the quantity of refrigerant leaked in kg;
LFL is the lower flammability limit in kg/m3.
The UL 60335-2-40 standard also specifies an air velocity of less than 0,5 m/s in the test room. Also in UL 60335-2-40:2022 there are requirements for temperatures from 15 °C to 35 °C.
Based on these requirements alone, most teams with test chamber construction capabilities will be able to fulfill them well. However, special consideration needs to be given to the requirements for explosion protection in test chambers. Because in the test process there are a lot of combustible refrigeration leakage, then there must be the risk of explosion, how to maximize the avoidance of these risks, you need to have enough experience and ability.
In this type of test chamber construction, comprehensive consideration of the severity of the danger, the protection of test personnel, the possibility of combustion and explosion, as well as the realization of the standard requirements of the test function.
First, we have to consider is the safety of personnel, the best way to protect the test personnel and test area is separated, the usual means is to use two rooms, the large room for leakage testing, the test personnel in the leakage test into the small room, even if there is a combustion explosion occurs in the large room, the small room will not be dangerous. The small room can be viewed through a camera or a glass viewing window to see what is going on in the large room. The glass viewing window between the large room and the small room, as well as the partition wall must be realized by using special construction materials.
Secondly, we need to ensure that in the event of an explosion, we can effectively minimize the damage to the building, in particular, there should be no permanent and difficult to repair cracks in the walls or the main load-bearing structure of the building cracking, bending or deformation of the situation. In this regard, the need to take a lot of measures, such as explosion-proof doors and windows, the use of explosion-proof windows and so on.
Third, the use of explosion-proof electrical components. Room will be used to electrical components, such as sockets, lamps, power tools, fixed wiring and so on. These components must be exploded they have a certain ability to prevent the explosion caused by the occurrence of. Need to mention in particular, the different areas of the room, the use of electrical components of different levels of explosion-proof.
Fourth, to meet the test room space for the temperature, humidity, wind speed and other requirements. According to the provisions of the standard, in the test, the test area of the wind speed requirements are higher, so how to control the wind speed at the same time can quickly adjust the temperature is a technical difficulty.
Fifth, the air exchange capacity of the test room also needs to meet certain requirements. It is after each test, the need to immediately release the refrigerant forced discharge to the outdoors, forced exhaust volume is also specified. At the same time, the test room will inevitably exist in the canned refrigerant or refrigerant piping, these cans or piping if leakage occurs, the test room should have the ability to sense the leakage, and the leakage of refrigerant forced discharge to the outdoors.
Sixth, the test chamber floor, wall, operating table, gas piping design and planning, need to minimize the risk of combustion and explosion. For example, the grounding of metal piping, the use of anti-static measures.
Seventh, the operation of the personnel specification requirements. Any operation in the laboratory, if not standardized, will also cause the risk of combustion and explosion. For example, not wearing electrostatic protective clothing, or the use of metal functions that may produce sparks and so on.
What we can do, according to your existing room conditions, to help the test room, including the room, electrical components, exhaust ducts, explosion relief ports, etc., reasonable layout, standardization of operating documents and requirements, training of laboratory personnel and a series of actions. Comprehensively protect the safety of the test room.
