Building insulation material
Insulation may be categorized by its composition (natural or synthetic materials), form (batts, blankets, loose-fill, spray foam, and panels), structural contribution (insulating concrete forms, structured panels, and straw bales), functional mode (conductive, radiative, convective), resistance to heat transfer, environmental impacts, and more.
Sometimes a thermally reflective surface called a radiant barrier is added to a material to reduce the transfer of heat through radiation as well as conduction.
This is a new generation eco-friendly foam blowing agent that is free of Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs), and Hydrofluorocarbons (HFCs) based on naturally occurring methyl methanoate.
Cutting it to accommodate electrical boxes and other obstructions allows air a free path to cross through the wall cavity.
One can install batts in two layers across an unfinished attic floor, perpendicular to each other, for increased effectiveness at preventing heat bridging.
Gaps between batts (bypasses) can become sites of air infiltration or condensation (both of which reduce the effectiveness of the insulation) and requires strict attention during the installation.
By the same token careful weatherization and installation of vapour barriers is required to ensure that the batts perform optimally.
Natural fiber insulations, treated as necessary with low toxicity fire and insect retardants, are available in Europe :[15] Natural fiber insulations can be used loose as granulats or formed into flexible or semi-rigid panels and rigid panels using a binder (mostly synthetic such as polyester, polyurethane or polyolefin).
Examples include cork,[16] cotton, recycled tissue/clothes, hemp, flax, coco, wool, lightweight wood fiber, cellulose, seaweed, etc.
They usually have significantly less thermal performance than industrial products; this can be compensated by increasing thickness of the insulation layer.
The clay coating gives the insulation a half hour fire rating according to DIN (German) standards.
[20] Cork, which is harvested from the Oak trees generally found in Portugal, Spain and other Mediterranean countries.
Notable challenges with cork include difficulty in maintenance and cleaning especially if the material is exposed to heavy use such as insulation for flooring.
[22] Sheep's wool has no reduction in performance even when condensation is present, but its fire retarding treatment can deteriorate through repeated moisture.
[23] It is made from the waste wool that the carpet and textile industries reject, and is available in both rolls and batts for both thermal and acoustic insulation of housing and commercial buildings.
Sheep's wool insulation has a long lifetime due to the natural crimp in the fibre, endurance testing has shown it has a life expectancy of over 100 years.
It can be used as internal insulation : between studs, joists or ceiling rafters, under timber floors to reduce sound transmittance, against masonry walls or externally : using a rain screen cladding or roofing, or directly plastered/rendered,[24] over timber rafters or studs or masonry structures as external insulation to reduce thermal bridges.
General procedure for retrofits in walls: US regulatory standards for cellulose insulation Skylights, solariums and other special applications may use aerogels, a high-performance, low-density material.
It also has very low emittance values "E-values" (typically 0.03 compared to 0.90 for most bulk insulation) which significantly reduces heat transfer by radiation.
Heat/ Thermal Insulation is a barrier material to resist / block / reflect the heat energy (either one or more of the Conduction, Convection or Radiation) to transfer from one side to another.
Urea-formaldehyde insulation releases poisonous formaldehyde gas, causing indoor air quality problems.
[31] Asbestos is a mineral fiber that occurs in rock and soil[32] that has traditionally been used as an insulation material in many homes and buildings.
It has also been found that asbestos can cause cancer when in friable form (that is, when likely to release fibers into the air – when broken, jagged, shredded, or scuffed).
When found in the home, asbestos often resembles grayish-white corrugated cardboard coated with cloth or canvas, usually held in place around pipes and ducts with metal straps.
Foam insulation often uses hazardous chemicals with high human toxicity, such as isocyanates, benzene and toluene.
Personal Protective Equipment is required for all people in the area being sprayed to eliminate exposure to isocyanates which constitute about 50% of the foam raw material.
However, manufacturers continue to provide cancer risk warning labels on their products, apparently as indeminfication against claims.
The OSHA chemical sampling page provides a summary of the risks, as does the NIOSH Pocket Guide.
In May 1999, the North American Insulation Manufacturers Association began implementing a comprehensive voluntary work practice partnership with the US Occupational Safety and Health Administration (OSHA).
The program, known as the Health and Safety Partnership Program, or HSPP, promotes the safe handling and use of insulation materials and incorporates education and training for the manufacture, fabrication, installation and removal of fiber glass, rock wool and slag wool insulation products.
