Polyisocyanurate is a thermoset plastic. It is also called PIR, polyiso, or ISO. It is usually made as a foam. It is used as rigid thermal insulation. It is similar to polyurethane (PUR) except that the proportion of methylene diphenyl diisocyanate (MDI) is higher and a polyester-derived polyol is used in the reaction instead of a polyether polyol. Catalysts and additives used in PIR is also different from those used in PUR.
PIR is used in rigid thermal insulation. PIR foam panels laminated with pure embossed aluminium foil are used in making of pre-insulated duct that is used for heating, ventilation and in air conditioning systems. Prefabricated PIR sandwich panels are manufactured with corrosion-protected, corrugated steel facings bonded to a core of PIR foam and used extensively as roofing insulation and vertical walls (e.g. for warehousing, factories, office buildings etc.). Other typical uses for PIR foams include industrial and commercial pipe insulation, and carving/machining media (competing with expanded polystyrene and rigid polyurethane foams).
Effectiveness of the insulation of a building envelope can be compromised by gaps resulting from shrinkage of individual panels. Manufacturing criteria require that shrinkage be limited to less than 1% (previously 2%). Even when shrinkage is limited to substantially less than this limit, the resulting gaps around the perimeter of each panel can reduce insulation effectiveness, especially if the panels are assumed to provide a vapor/infiltration barrier. Multiple layers with staggered joints, ship lapped or tongue & groove joints greatly reduce these problems.
PIR insulation can be a mechanical irritant to skin, eyes, and upper respiratory system during fabrication (such as dust). No statistically significant increased risks of respiratory diseases have been found in studies
PIR is at times stated to be fire retardant, or contain fire retardants, however these describe the results of "small scale tests" and "do not reflect [all] hazards under real fire conditions"; the extent of hazards from fire include not just resistance to fire but the scope for toxic byproducts from different fire scenarios. A 2011 study of fire toxicity of insulating materials at the University of Central Lancashire's Centre for Fire and Hazard Science studied PIR and other commonly used materials under more realistic and wide-ranging conditions representative of a wider range of fire hazard, observing that most fire deaths resulted from toxic product inhalation. The study evaluated the degree to which toxic products were released, looking at toxicity, time-release profiles, and lethality of doses released, in a range of flaming, non-flaming, and poorly ventilated fires, and concluded that PIR generally released a considerably higher level of toxic products than the other insulating materials studied (PIR > PUR > EPS > PHF; glass and stone wools also studied). In particular, hydrogen cyanide is recognised as a significant contributor to the fire toxicity of PIR (and PUR) foams.
Despite this PIR insulation is generally regarded as being more fire resistant than PUR insulation.
100mm PIR insulation board (cited as the RS5000 product of Celotex, a Saint-Gobain company) was proposed as the columnar and horizontal external insulation to be used in the refurbishment of Grenfell Tower, London; subsequently "Ipswich firm Celotex confirmed it provided insulation materials for the refurbishment." On 14 June 2017 the block of flats, within 15 minutes, was enveloped in flames from the fourth floor to the top 24th floor. The causes of the rapid spread of fire up the outside of the building have yet to be established. It should be noted that flames can occupy the cavity between the insulation material and the cladding, and be drawn upwards by convection, elongating to create secondary fires, and do so "regardless of the materials used to line the cavities".
Schöfflisdorf
Schöfflisdorf is a municipality in the district of Dielsdorf in the canton of Zurich in Switzerland.
It is situated in the Wehntal.
Schönenberg, Zürich
Schönenberg is a former municipality in the district of Horgen in the canton of Zurich in Switzerland. On 1 January 2019 the former municipalities of Hütten and Schönenberg merged into the municipality of Wädenswil.
Schwerzenbach
Schwerzenbach is a municipality in the district of Uster in the canton of Zurich in Switzerland.
Seegräben
Seegräben is a municipality in the district Hinwil in the canton of Zurich in Switzerland.
Aathal, Aathal-Seegräben, Aretshalden, Sack, Ottenhausen and Wagenburg.
Brahmo Samaj
Brahmo Samaj is a Hindu reform movement founded in the 19th century in India.
During the 19th century Indian society had various social and religious problems in the Indian society. Several movements were started to help reform the society various "samajs" were formed. These included the Prathna Samaj, the Satya Shodhak Samaj, the Theosophical Society, and others. The Brahmo Samaj was one of these. It was founded by Raja Ram Mohan Roy in the year 1828. It can also be said as the first attempt by the Indians to reform their religion and end its harmful practices. While under Keshab Chandra Sen it was able to make great progress and set up many branches across India. The Brahma Samaj helped reform the Indian society.
Some of its important reforms were to end the practice of sati (the widow committing suicide on her dead husband's funeral pyre), opposing the worship of many gods, ending costly sacrifices and meaningless rituals. The movement proposed the belief that God is omnipresent, promoted inter-caste and widow remarriage, opposed child marriage and polygamy, and more.
The following doctrines, as noted in Renaissance of Hinduism, are common to all varieties and offshoots of the Brahmo Samaj:
Chirnihiv
Chernihiv () is a city in Ukraine. About 300,000 people live there.
Chirnihiv is twinned with:
Seuzach
Seuzach (Swiss German: "Söizi" []) is a municipality of the district Winterthur in the Swiss canton of Zurich.
Offenburg
Offenburg () is a city in the German state of Baden-Württemberg. In 2013, about 57,000 people lived there.
Landeck
Landeck is a town in the Austrian state of Tyrol. It is the capital of the district of Landeck.
Stadel bei Niederglatt
Stadel is a municipality in the district Dielsdorf in the canton of Zurich in Switzerland.
Stäfa
Stäfa is a municipality of the district of Meilen in the canton of Zurich in Switzerland. It is near Rapperswil on the north bank of the Lake Zurich in the Pfannenstiel region.
Stallikon
Stallikon is a municipality in Affoltern in the canton of Zurich in Switzerland. About 3,438 people lived in Stallikon in 2015.
Zenica
Zenica is the fourth-largest city in Bosnia and Herzegovina. It is about north of Sarajevo and is on the Bosna river, surrounded by a mountainous and hilly landscape. The city is home to 115,134 inhabitants as of 2013.
Ústí nad Labem
Ústí nad Labem (, ) is the seventh-largest city in the Czech Republic. The area has many mountains. The city is where the Bílina and Elbe rivers join.
Ústí is twinned with:
Thur (Switzerland)
The Thur is a river in north-eastern Switzerland. The length is . Its source is near the mountain Säntis in the southeast of the canton of St. Gallen. In this canton it flows through the Toggenburg region and the town of Wil. After Wil it flows through the canton of Thurgau and its capital Frauenfeld. The final of the river are in the canton of Zurich. It flows into the river Rhine on the border with Germany, south of Schaffhausen.
Bettendorf, Haut-Rhin
Bettendorf is a commune. It is found in the Haut-Rhin department of eastern France.
Lecce
Lecce is a historic city in southern Italy. It is in the Apulia region. In 2015, 95,766 inhabitants lived there.
Bettlach
Bettlach can mean:
Bettlach, Haut-Rhin
Bettlach is a commune. It is found in the Haut-Rhin department of eastern France.
Steinmaur