Polyisocyanurate
Polyisocyanurate (PIR or Polyiso) foam insulation is known for its high thermal resistance as well as fire resistance compared to other foam insulants. Its behaviour under fire conditions has though recently come under great scrutiny since the role of Celotex RS5000 PIR insulation in the Grenfell tragedy in London UK in 2017. It has commonly for many years been used in commercial roofing systems, wall insulation, cladding systems in many modern buildings and as a component in structural insulated panels (SIPs). It ia also commonly used for industrial and commercial pipe insulation, laminated to aluminum foil and used for fabrication of pre-insulated duct that is used for heating, ventilation and air conditioning systems.
The core materials of PIR are similar to those used in 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. The resulting chemical structure is significantly different, forming isocyanurate groups which the polyols link together, giving it a complex polymeric structure.
This structure means that PIR was generally accepted as performing significantly better than PUR against fire, previously thought to have excellent fire behaviour from being tested to high standards, the Grenfell tragedy bought much of this into question. Shortly after the fire on June 23 2017, the Police confirmed that small-scale fire tests had been carried out and Detective Superintendent Fiona McCormack commented "The insulation was more flammable than the cladding. Testss how the insulation samples combusted soon after the test started."
[edit] Related articles on Designing Buildings
- Acrylic.
- An in-depth look at Environmental Product Declarations EPDs.
- Celotex RS5000 PIR insulation.
- Composites.
- ETFE.
- Fire behaviour of expanded polystyrene.
- Forever Chemicals.
- Glass reinforced plastic.
- Grenfell Tower fire.
- Insulation.
- LPCB certification and Kingspan.
- Loss Prevention Standard.
- Packaging.
- Plastic.
- Polyethylene.
- Polyurethane (PUR).
- Polystyrene.
- Persistent organic pollutants (POP)
- Phenolic foam insulation.
- Polyurethane spray foam in structurally insulated panels and composite structures..
- Sandwich panel.
- Specifying insulation for inverted roofs.
- Thermal insulation for buildings.
- Transparent insulation materials.
- Types of insulation.
- Types of plastic in construction.
- What do design professionals need to know about U-value calculation conventions?
Featured articles and news
What it is and how to use it.
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.
70+ experts appointed to public sector fire safety framework
The Fire Safety (FS2) Framework from LHC Procurement.
Project and programme management codes of practice
CIOB publications for built environment professionals.
The ECA Industry Awards 2024 now open !
Recognising the best in the electrotechnical industry.
Sustainable development concepts decade by decade.
The regenerative structural engineer
A call for design that will repair the natural world.
Buildings that mimic the restorative aspects found in nature.
CIAT publishes Principal Designer Competency Framework
For those considering applying for registration as a PD.
BSRIA Building Reg's guidance: The second staircase
An overview focusing on aspects which most affect the building services industry.
Design codes and pattern books
Harmonious proportions and golden sections.
Introducing or next Guest Editor Arun Baybars
Practising architect and design panel review member.