The range of materials used can be classified into four main types:
Insulation: Glass and Ceramic fabrics and needle mats
Reinforcement: Stainless wire mesh, Aramid fabrics or Glass fabrics
Chemical Barrier: PTFE films or Fluoro-Elastomers
Chemical Barriers and duct covers
EPDM SuperSpan Mark II Flextra Ethylene Propylene(EPDM) A low-cost, high-performance compound with excellent ozone, oxygen and chemical resistance including ammonia and mild acids. EPDM can operate at 150 deg C constant and has excellent low-temperature resistance.
FLUOROELASTOMER SuperSpan Mark III wire/F Fluoroelastomers (FKM) manufactured in the USA by DuPont (Viton) and Dyneon (Fluorel). This family of elastomers has outstanding resistance to chemicals, oils and heat compared to other elastomers. FKM is excellent for high acid conditions typically found from the air heater to the stack and is acceptable for use where low concentrations of ammonia are possible due to ammonia slip (<10ppm). 205 Deg C operating and 400 Deg C excursion.
FLUOROPLASTICS SuperSpan Flextrachem and FlexTex A family of compounds that have excellent heat and chemical resistance. Based on the coating technique and film thickness, these materials can be zero porosity and have the ability to resist chemical attack in the harshest environments. Upper temperature of 316 Deg C constant operating.
(Viton is a registered trademark of DuPont and Fluorel is a registered trademark of 3M).
SILICONE (SL) Silicone has a poor resistance to chemical environments and wet conditions and should not be used in any flue gas, or corrosive application. Silicone should be restricted to hot dry applications at 260 Deg C.