We can't discuss torch applied systems without first talking about propane safety.  Propane or LPG (liquefied Petroleum Gas) is a fuel gas that is compressed and stored in pressurized tanks.  The tanks or cylinders come in different sizes with the most common for our industry ranging  between 20 and 100 pound cylinders.  A small tank being used in cooler weather may frost.  Let it thaw naturally and never torch the cylinder to defrost it.  Propane cylinders should be kept upright and chained/secured in that position .  They should be positioned in areas away from equipment or vehicle traffic.  They should be located away from any heat activity so they don't over heat.

Use care when lighting a torch and when handling a lit torch.  Check all connections and hoses for leaks before you start.  Never use a match or cigarette lighter to light a torch.  Use a spark generator.  Some torches are designed so they can be laid down while lit.  Make sure the surface is not combustible and never leave a lit torch unattended.

Don't torch directly to a combustible surface such as plywood.  These should be covered with a non-flammable material like a base  ply of asphalt felt.  Oil, grease, or dust can accumulate at wall terminations on existing structures so extra caution should be used when torching in these areas.  Don't apply the torch to an area you cannot clearly see.

A fire can smolder for an hour or more before bursting into flames.  It's important to have a fire watch for at least one hour after the last torch is turned off.  Inspect above and below the roof deck for any hot spots. 

Be careful not to burn yourself or the building when working a torch applied system.