Safety for Cold store use refrigerant NH3

[nhoksockiu]

Hi guys,

I'm a final-year student in Vietnam, my dissertaion is design Refrigeration system for cold store by R717.
I know R717 very dangerous if it leakage through piping line in Cold store.

Everyone can recommend me how to protect piping line or detect leakage as soon as possible.

[sterl]

1) Mitigate the risk. Put the piping and the control/ isolation valves above the roof. This may mean a penthouse for the evaporators...And a penthouse has maintenance advantages in terms of servicing the evaporators.
2) Many detectors available that will detect ammonia in air at 5-ppm which is below the threshold for identification. Not many are intended for use in refrigerated spaces: You will want to specify something proven for refrigerated space use at high air velocities.
3) Coatings are available and fairly inexpensive for use on surface of steel pipe. This normally applied by the pipe insulators; and is proven effective at mitigating corrosion even should the insulation system fail or be decayed.
4) Control and isolation valve stations now available with welded pipe connections. There are still assembly joints for the valves themselves but the design removes flange bolts and their gaskets from the list of concerns.
5) Design pipe supports and saddles with consideration of expansion and contraction. Although there are no temperature differences like those for steam pipes and no real need for expansion joints, the pipes still shift and require installed slopes....The support arrangement, roof penetrations and valve station arrangement needs to accomodate the shifting and changing temperatures.
6) Installation quality assurance can take a number of forms and what portion of it is cost effective will start an extended discussion. Welder's procedures should at minimum require weld/welder identity and the circuit evacuation/ integrity test/ leak test procedures and requirements should be well established and third party witnessed.

[nhoksockiu]

Thank Sterl