Question:

I wonder if you could help us with a Query in regard to duel fuelled (wood and Gas) pizza ovens.
We’ve been asked to fit two and one previously at another site Duel Fuelled Pizza Ovens. We would like to know people’s opinion in regards to these units and any implications with fitting these in sites? An honest opinion would be great please. We understand that if they are fitted within a kitchen that no other extraction unit can be fitted in that room and that they require an extraction fan in the flue if exiting the kitchen directly without a canopy. These would then need to be interlocked to the gas supply and a CO2 monitor fitted in the room also interlocked to the extraction fan. Also, in regard to burning embers within the pizza oven after service, what would be the correct manner in which the installation should fitted, i.e., temperature sensor within the flue preventing the extraction from being turned off until an optimum temperature is reached and the embers burnt out?
I look forward to any response please.

Replies:

1. I suggest you contact Lee Preston at Inox Fabrications Ltd Email- Lee@inoxfabrications.com Web- www.inoxfabrications.com
2. Refer to the Guidance document on solid fuel appliances – Guides – ceda
3. Firstly, If its duel fuel it must be approved by DEFRA as an approved appliance for use in a smokeless zone, either the appliance is approved or the fuel is approved, wood is not an approved fuel for use in smokeless zones and by default the appliance must be approved (not many places in the U.K are exempt or do not fall under a smokless zones)
   Secondly if you are burning wood, it should have a dedicated duct to atmosphere and not run into a common duct, you can only use a common duct on gas only, there mere fact its duel fuel says it needs dedicated extract.
   The spec and regs does not say you that you can’t have another extract system in the same room, the issue is having one running and then for example turning off the wood burning extract off and then the main extract pulling smoke and fumes from the wood burning appliance, so you could in theory link the two systems so they are balanced and can only work at the same time.
   I would then link the wood burning appliance system with a C02 monitor so if CO2 is detected (say 1 hour after service is shut down) the system kicks back in.
   The operator should put in place a standard operating procedure SOP to stipulate how they will handle end of service  burning embers, but if a CO2 monitor is fitted that deals with fume build up but not potential the fire risk, it can be as simple as the oven gets stopped being used at 9pm and the wood left to burn out, for two hours,  embers/ash are then  removed into an steel bucket, doused and removed to atmosphere.
4. In brief my view would be; Generally this type of oven will need a direct extract with double wall. Burning wood will create the need to clean the duct more regularly, maybe ever 6 weeks due to the effe4cts of the sap. There might be “clean air act” issues. Almost certainly will need CO & CO2 monitors and indeed control to switch the extract back on overnight if the levels rise above permissible levels, without this there’s a risk that you kill the prep chef or cleaner. Duel fuel of just wood always sounds like a great idea, generally isn’t.
5. I suggest they read and work to section 10 of the ceda Industry Guidance Final and include CO sensors rather than CO2.