SFPE Discussions

Warehouse with mechanical smoke extraction

Does anyone know of a large warehouse in Auckland that has mechanical smoke extraction? We’re doing some preliminary investigations into what might be required and our client is keen to see an existing installation first. You can email me at rob@nelligan.co.nz to discuss rather than post here, thanks!

I can’t provide an example, although I know of one down south although I can’t remember the address without looking it up. The fans were small jet engines and the electrical demand was significant…
My experience of looking at smoke control in warehouses in the past is that there are a number of traps. Inlet air is a big issue, since the air volumes are huge and there are racks against the outside wall. even if not fire rated, these are often concrete to protect the walls from errant forklifts.
If you use the roller doors and have them opening on fire, then they must meet AS11668 as a smoke control system. Fire rated cable, live side supply, switch gear (with limitations on isolation switches), fire rated drive motors and connections. The average belt drive industrial door motor won’t work.
Warehouse doors are also usually only on one side, and often under a canopy, so air distribution isn’t great in a large warehouse so you can get dead spots or smoke dragged to places you don’t want it.
Natural ventilation will give you larger air volumes especially in tall spaces, and self corrects for larger fires, but the inlet air area problem is worse.
Another item to consider is the structural support of the fans on the roof and the resulting cost. In one I saw in the past, the structure had to be increased due to the weight of the fans. fabricated steel portals are very efficiently designed and don’t usually have the capacity to take several tons of plant on the roof without extra work.
Geoff

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Thanks for your wise words Geoff. I have warned the client about the fire rated cables, motors etc… but didn’t consider the extra fire rated roof structure to support the fans, I’ll add that to our argument for them to fit sprinklers!