Our building spec asks for "glass foam" to insulate trace heated fuel piping. Would this be polyurethane foam? Some special additives in it? Wouldn't just steel plated rockwool be a superior solution?
lauri
I found also a couple of definitions by searching the WEB:
Cellular glass
A lightweight expanded glass with small cells, produced by a foaming process;
also known as foam glass.
Glass wool
Mineral fibre produced from molten glass. Also known as glass fibre.
Mineral wool
A generic term for mineral fibres of a woolly consistency, normally made from molten glass, rock or slag. The term embraces glass wool, stone wool
and slag wool.
I have been inspecting corrosion under insulation for a number of years and found a lot of corrosion on non cellglass systems.
DO NOT USE ROCKWOOL OR ANY FIBER AS IT KEEPS MOISTURE AND WATER.
It is Cellular glass (Foamglas) you need ref. MGP's reference!
Foamglas with it's open cell structure will drain moisture and ingress water from the pipe wall by gravity. Foamglas is used for fire resistance, but often you would need an additional 50 mm with ceramic fibres, however the ceramic fibres should be placed on the outside of the cellglass, not against the pipe wall. If you are using a steel sheeting, make sure to drill some drainage holes at the 6 o'clock position to drain out moistrure.
Make sure all vertical ends have a drainage hole.
If your fuelgas piping is 316, make sure that your trace heating has a thermostat to avoid a suface temperature (at the pipe under the insulation) to increase above 60 deg. C for the piping as you may experience SCC.
Dow Cornings foam Glass insulationis used in the petrochem industry where high temperature heating fluis such as Dowtherm or Therminol are used. There have nbeen instances where the fluid has leaked into fibrous insulation. The increase in surface are has resulted in spontaneous combustion of the fluid.
Visit the Therminol website for more details.
I can only assume that whoever has specified FoamGlas is concerned from this aspect. Before changing it check your PI policy. Sharing knowledge is a way to immortality