This is bit of a rare technical issue, I don't know if you know anyone who may have experience of this particular problem... At the top of the concrete bridge pylon here in Vladivosotk is a slip-form Peri formwork shutter. It's enclosed, in order to maintain protection from the weather for the workers but also to maintain reasonable air temperature for concreting. Hi, Now that the temperature is dropping to below minus 10C the contractor (not us) on a bridge project in East Russia have installed diesel powered space heaters (the things that look like little jet engines). There are 12 of them up on the enclosed formwork. Obviously being an enclosed space of timber construction the fire risk is, ahem, 'elevated' shall we say. I'm aware infra-red heaters are an alternative as are concrete addatives but I didn't know if there were any other cost effective (safer) solutions that we could present to our clients. Advice from anyone with experience of "heating enclosed formwork" would be greatly appreciated. Kind regards James