ammonia ventilation

[me2016]

Dear Sir

we have ice cream production room with dimensions 40m*40m*5m and sometimes we face ammonia leakage so please how we make ventilation in short time. your suggestion & ideas highly appreciated

Note: we use ammonia for refrigeration(Hardening Tunnels and continuous freezers)

Thank you

 

[trashcanman]

First, find and repair the leak. In the meantime, provide an exhaust fan @ 10 air changes/hr. It can be manually controlled or triggered by an ammonia "sniffer".

 

[me2016]

Do we need inlet fan?

Thanks

 

[chicopee]

We know that ammonia has a pungent odor, however, you can not just base a fan on odors only unless they are considered nuisance to the workers. You should size a fan based on the acceptable breathing level known as the threshold limit values (TLV) published by the American Conference of Governmental Industrial Hygienists (ACGIH) if persons entering the ammonia storage and equipment room to perform tasks. To size the fan CFM, You'll need to estimate the maximum concentration, the TLV, time to evacuate the vapor under steady state conditions and room volume. Nonetheless SCUBA respirators will be required for any emergency repair. In engineering rooms ( not talking about engine rooms) where engineers do their work and make copies of their blue prints with ammonia copying machines, a local exhaust fan will be needed since the ammonia vapor emitted from the blue prints will be overwhelming but not necessarily exceeding the TLV short term exposure limit (TLV-STEEL) limit from ACGIH. In addition Ammonia vapors are considered flammable, however, since its lower flammable limit has a concentration level much greater than ACGHI TLV,the onset of fire is substantially minimized unless you have impingement of vapor on spark producing equipment. One last thing is that the odor thresholds of contaminants are much lower than their threshold limit values, therefore, realize that awif of ammonia does not necessarily mean that a respiratory or fir fire hazard exist.
" Do we need inlet fan?" use exhaust fan otherwise inlet fan will distribute the vapor throughout the building.

 

[Ziggypump]

CHECK THE CODE!!!! Per IMC 10 ACH is not enough, 30 ACH minimum. Read the code, check out the IIAR standards.

Ammonia is not something to trifle with. Fix the leak, as this is probably contaminating the product in the freezer.

 

[me2016]

Dear chicopee,

if we do not use inlet fan please what about the pressure inside the room?

Thank you

 

[Ziggypump]

Well that's a loaded question. What would you want it to be? This should be part of the design that you come up with.

 

[willard3]

You should hire an Engineer who is familiar with ventilation rather than trying to bootstrap this.

 

[chicopee]

I indicated an exhaust fan to remove or dilute ammonia vapor during a leak.

 

[lilliput1]

Refer to ASHRAE 15 Safety Standard for Refrigeration Systems and Refrigerant Leak Detector Panel (with exhaust fan control). The exhaust requirement depends on the amount of refrigerant (ammonia here) that can leak out. This would be the content of the largest system that can leak into the room. Part of the exhaust need to be constant, the remainder emergency exhaust upon leak detection. The refrigerant monitor panel is usually located outside the room by the doorway. It typically has about 8 remote sensors that need to be located low around the equipment that has potential to leak. Anyone of the sensor can activate the panel in stages depending on the concentration measured. Stage 1 usually is to issue warning to the operator & occupants and flash strobe light. Stage 2 could be activate the emergency exhaust fan, open makeup air louver dampers, flash alarms and sound alarm horns. In addition to the alarm light and horn on the panel, provide additional remote alarm horns and lights inside the room at each entrance/exits. Outdoor makeup air should be provided by opening low louver dampers. Locate air intake louvers and exhaust air pickup point low and in manner to completely sweep the room floor.

 

[Compositepro]

The exhaust air pick-up point should be located high since ammonia is lighter than air.