Hi 9, the most commonly available solution will be LPG fired "jet engine" heaters. These are very effective but do introduce very significant fire risks, the magnitude of which will depend on a number of factors. The gas bottles, the connections, the positioning of the jet, the nearness of combustible goods, ventilation needs, moveability etc will all need to be looked at very closely if you are to go down this route. Your fire insurers will not be keen on this option but may be persuaded if you can convince them that your risk controls are good. They also come in a diesel fuelled variety (stinky, liquid fuel filling and storage plus all the above). Infra red radiators on poles would provide a very localised heat source and maybe an option for a staff rest room, as will LPG pole mounted heaters but with the above caveats. There's a good chance somebody will suggest thermal knickers and running!

Thanks for the replies, Have sent you a PM David

And please do not forget a good part of the output of the cheaper liquid/ lpg fuelled heaters (those where the flame exhaust is exhausted out of the front) will be water vapour, leading to excess humidity. Cold, clammy. Major problems for any staff with respiratory problems.

To expand on John Murray's comment at #6, excess humidity from heaters of the types he mentions can also adversely affect items stored if they are vulnerable to moisture. The same goes for unpainted metal fixtures, etc. Older forum users may remember publicity from the late 1970s/early 1980s about civil servant Clive Ponting finding and reporting that MOD warehouses for barbed wire and similar commodities were heated. If barbed wire is prone to deterioration through rust during storage, perhaps there was some sense in having low level heating inside the warehouses in order to keep their contents dry. My mention of this aspect was prompted by having read recently a fascinating book about disused stone mines, notably near Bath, being used for storing vast quantities of ammunition safe from aerial bombing during WW2. Moisture and high humidity tend to be prevalent in most mines, including the ones near Bath. After it was realised that steel shellcases and ammunition boxes were very prone to corrosion and wooden boxes tended to disintegrate through rot, a fortune was spent on measures to try and control the humidity in the underground stores. p.s. 9yally - On a whimsical note, if the heating in the warehouse has "gone" as you state, has anyone thought about going to search for it, and with what outcome? Also, does the warehouse heating have a habit of absconding?!! :-)