Diamond Central - Executive Summary
Diamond Central is a fruit packing plant, we use anhydrous ammonia as a refrigerant in our cold storage operation. |
We have used ammonia as a refrigerant for more than 80 years with no release that caused a threat to our community.
Our refrigeration operators are members of The Refrigeration Engineers & Technicians Association and receive much of their technical training through this association. They have been involved with forming this program. Our engineers receive continual training for handling ammonia in our process.
We have complied with OSHA'S Process Safety Management Program since June 1995. We have a written emergency response plan which we work with our local fire dept. in the event of a release.
A worst case release for us would be the loss of 25,540 lbs of ammonia which could travel 2.7 miles. This is however unlikely in that a ammonia leak would be detected early by smell or alarm and we have a series of valves to turn off which would limit the amount of ammonia relea
Our fire dept. is 200 yards from our plant, they will respond to a leak when called and they will be in charge of community safety, Shelterling in place will protect people most of the time until a ammonia cloud passes. In a rare situation people may have to evacuate the area, the fire dept. would notify the public in that event.
In order to prevent a release of ammonia we do the following:
a. All ammonia processes are in accordance with the American Society of Mechanical Engineers.
b. CA rooms are equipped with ammonia detectors which sound an alarm at 25ppm.
c. Engine rooms and cold storages are visually inspected daily.
d. Compressor oil is changed and inspected yearly.
e. Ammonia equipment is monitored by our refrigeration engineers.
f. Maintenance is done as per equipment manufacturers recommendations and per Refrigeration Engineers Technicians Associations guidelines.
g. State electrical inspections are done each year.
(2) Alternative Scenario
While unloading a cold storage room on the northwest corner of Diamond Central, the lift truck driver hits a refrigeration coil and breaks a hole in it. He is showered with liquid ammonia, but is able to make it to the shipping office within two minutes.
Charles Tuttle calls Don Poole on his radio and tells him what has happened. Since it is a liquid and not a vapor leak, Don tells Tuttle to call our emergency contact number. They will call the fire department and call the other three Diamond process operators.
Don then goes directly to the engine room and starts the emergency shutdown procedure. He knows that the area valve and room control valves for the room are located in a mezzanine above the room. He takes his meter to the computer room and checks out the mezzanine hallway. It is below 300 ppm so he looks down the hall. There is n
o dense fog or liquid spray so he does not need his level B suit. He calls Tuttle and tells him that he is going down to shut the valve off. After he puts on his SCBA he enters the hallway. At the area valve, the level is 200 ppm so he continues on to the room valve. The ammonia level is 500 ppm but skin damage does not occur until 10,000 ppm so he is ok. He shuts the room's liquid valve and manually opens the backpressure regulator.
He now opens the North exit doors to the mezzanine that lead outside, sees the level is 900 ppm outside, that the fire department has shut off Chevron Drive at Mud Alley and Lingren Road. He is on a balcony just above the doorway to the hall that leads to the leaking room doorway. As he goes down the stairs, he walks into a gentle breeze and his meter quickly drops to 0 ppm. As he passes in front of the door his meter goes back up to 900 ppm. He then shuts the door.
Within 15 minutes the homes on the North side of Chevron Road which had seen lev
els up to 300 ppm are now seeing less than 25 ppm.
For the next two days small vent fans are used to slowly air out the room.