18 TECHNICAL CONSIDERATIONS For outdoor pipework a UV resistant insulation should be specified to prevent degradation of the material and loss of thermal performance. ArmaFinish 99 paint can be used to protect AF/ArmaFlex Class O from UV damage, or alternatively HT/ArmaFlex is made from EPDM rubber which is suitable for outdoor use. Pre- covered insulation products such as Arma-Chek Silver are also available to provide additional protection. Air is always contaminated with pollutants to some degree, such as man-made volatile organic chemicals, industrial fibres, acidic particles of dust, and spores of mould and bacteria. Whilst breathing these may not result in any immediate signs of ill health they may all contribute towards “building related symptoms”. The specification of ArmaFlex dust and fibre free insulation systems with added Microban® antimicrobial protection helps minimise the impact on indoor air quality. Selecting dust & fibre free insulation on ductwork systems can minimise any potential contribution to indoor air pollution. The emissivity of a material is the relative ability of its surface to emit energy by radiation compared to energy radiated by a black body at the same temperature. The dull, black surface of ArmaFlex is advantageous on cold pipework since the surface temperature absorbs more energy, keeping the surface temperature warmer and above the dew point at reduced insulation thicknesses. The more reflective a material, the less energy it radiates. Silver coverings such as Arma-Chek Silver for instance can be recommended to reduce heat losses from hot applications by reflecting energy from the insulation surface back towards the pipe. SURFACE EMISSIVITY INDOOR AIR QUALITY UV EXPOSURE