Case Studies » Denholm Seafoods
A visit was made to the Denholm Seafood site in Peterhead, Aberdeenshire in May 2015 to consider compliance in respect of the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).
Activities carried out on-site incorporate specialist fish reception, cleaning and packaging facilities. While operations are not particularly complex, processing routinely involves hazardous refrigerant – albeit this is generally within confines of chiller plant. The DSEAR focus was primarily upon arrangements associated with the Ammonia refrigeration plant and potential flammable vapour release from equipment failure or maintenance activity.
The solution provided
Ammonia is contained within plant systems associated with extensive chilling systems on-site and including compression, condenser & evaporation stages. Ammonia does not readily burn or sustain combustion, but with a narrow fuel-to-air mixtures of 15–28% in air it may ignite and lead to fire or explosion.
Anhydrous ammonia is a clear, colourless liquid or gas, free from visible impurities and liquid Ammonia expands 850-fold when evaporating. Ammonia reacts with chlorine also.
It is a moderate fire risk as Minimum Ignition Energy is 100mJ as compared to 0.25mJ for Propane. Vapour release may lead to explosion if within flammable range and it’s important to note that if Ammonia is contaminated with lubricating oils its flammable range can significantly increase.
All existing controls were thoroughly reviewed and the overall risk deemed acceptable. There were a number of improvement actions suggested and these were clearly explained to the site engineers.