Will probably never see this ever again, hope to get the pics off work. Just finishing off a major refurb on a supermarket in a large shopping centre, three racks on R404A, air cooled condensers undersized for noise reasons (slow fans), capacity compensated for by evaporative coolers built around condensers (vertical air discharge, evap cooler underneath) reducing temp of air onto condensers.
System not quite finished being commissioned, metal fab guys were building large sound baffles around the condenser area, they had removed the filter materials around the evap coolers (straw) due to fire hazard as they were grinding, welding and oxy cutting steel.
Somehow they still managed to ignite the straw, placed underneath one condenser for safe keeping (smart move!). the air being drawn through the condensers fuelled the burning straw underneath, the fire toasted one condenser completely until the pressure blew both the pressure relief on the receiver and then the copper tubes of the condenser now creating an oil fire on the other two. All three condensers blew, releasing around 1100 kg and burning the **** out of the roof of the building.
The metal guys got off the roof in time to try to blame the fridge contractors for the whole fiasco and I just finished starting the racks back up on temporary condensers (9 weeks for new ones) with a new 1100 odd kgs. Store was none too impressed, lost all stock two weeks before christmas, shut down for one day and no refrig stock for a week! Not to mention the new pipework needed as the fire brigade soaked the lot and most of the condenser run was filled with water! Got to love supermarkets... anything can and DOES happen.