FAQs

Here are some of our most frequently asked questions on MIMA and Mineral wool. If you click on a question it will show you the answer.

• What is MIMA (formerly Eurisol)?
  MIMA stands for the Mineral Wool Insulation Manufacturers Association. We are a trade body that
  represents the UK manufacturers of mineral wool insulation.;
• Who are the members of MIMA?
  Knauf Insulation, Rockwool and Superglass.;
• What is mineral wool?
  Mineral wool is a non-metallic, inorganic product manufactured from a carefully controlled mix of raw materials, mainly comprising either stone or silica which are heated to a high temperature until molten. The molten glass or stone is then spun and formed into a flexible, fibrous mat for further processing into finished products.
  
  The exceptional thermal, fire and acoustic properties of mineral wool derive from the mat of fibres that prevents the movement of air, and from mineral wool’s inert chemical composition.
  
  It is a very versatile material, and can be manufactured to many different densities to give varying properties, formed in various shapes and faced with a variety of sheet materials. The range of products includes loose granular material used for blown insulation of cavity walls, slabs for walls, rolls for loft insulation through to pre-formed and faced pipe sections, ceiling tiles and acoustic panels.;
• Is mineral wool recyclable?
  Mineral wool can be recycled. Contact individual MIMA member for more information.;
• Does mineral wool have any recycled content?
  Yes, mineral wool insulation has up to 80% recycled content depending on the product. Contact individual MIMA members for more information.;
• Does mineral wool insulation perform well in fire?
  Mineral wool insulation is non-combustible, achieving a Euroclass Reaction to Fire classification of either A1 or A2-s1, d0. Therefore, mineral wool insulation does not contribute significantly to fire growth and does not produce any significant smoke or flaming droplets.
  
  Additionally, non-combustible building materials, such as mineral wool insulation, do not burn and therefore do not produce any significant toxic gases in a building fire. Smoke and other toxic gases are known to be a leading cause of death in building fires.;
• What is the difference between glass wool and stone wool?
  Glass wool is manufactured from molten silica. Stone wool is manufactured from molten rock.;
• Is mineral wool carginogenic?
  No. A Health, Safety and Environment information leaflet is available on request.;
• What is the Global Warming Potential of mineral wool?
  Mineral wools do not contain ozone-depleting or global warming substances, nor are these used in their manufacture. It has a Global Warming Potential (GWP) of less than 5.;
• What is the Euroclass Reaction to Fire classification system?
  The Euroclass Reaction to Fire classification system is the European method for determining the reaction to fire of construction products in accordance with EN ISO 13501 Part 1.
  
  The Euroclass system ranks materials from A1 to F. The Euroclass system is made up of the following principal classifications:
  A1 and A2-s1, d0 – Non-combustible
  B to F – Combustible
  NPD – No performance determined
  
  The Euroclass system also classifies materials based on whether, and the extent to which, they produce smoke and burning droplets:
  s1, s2, s3 – Smoke production (s1 = least smoke)
  d0, d1, d2 – Flaming droplets (d0 = no flaming droplets)
  
  Below is an example of how Euroclass classifications are presented in product documentation, such as the Declaration of Performance (DoP):
  • B-s3, d2
  
  A1 rated products do not have a classification for smoke production or flaming droplet formation because they do not contribute to fire at any stage, meaning that they do not ignite, spread flame, produce significant heat, smoke, toxic gases or flaming droplets.;
• What is the ‘Declaration of Performance’ (DoP) of a construction product?
  The Declaration of Performance (DoP) is a legally required document for products covered by a harmonised standard under the Construction Product Regulations (CPR). It must be signed and made publicly available by the construction product manufacturer.
  
  The DoP contains key product information, including:
  • the manufacturer’s information
  • the intended use(s) of the product
  • the product type
  • the declared performance of each relevant essential characteristic and the reference standard used
  • the information of any notified body involved with the assessment of the product
  
  The essential characteristics are properties of construction products that have a significant impact on their performance in a building. It is important the check the DoP to ensure that a construction product meets the performance requirements for its intended use.
  
  The Euroclass Reaction to Fire classification is an example of an essential characteristic under the CPR. Many harmonised product standards, including those for mineral wool insulation, require testing and declaration of the Euroclass Reaction to Fire classification.;
• What do building regulations say about the combustibility of insulation materials?
  The ban on combustible materials in external walls
  
  In England, Regulation 7 of the Building Regulations requires the use of only non-combustible materials through the external walls of relevant buildings. Non-combustible materials are defined as those which do not achieve a Euroclass rating of A1 or A2-s1, d0.
  
  Scotland, Wales and Northern Ireland have also introduced bans on the use of combustible materials in the external walls of relevant buildings.
  
  Due to its non-combustibility, mineral wool insulation can be used in the external walls of all buildings across the UK nations.
  
  Definition of ‘relevant building’
  
  The definition of ‘relevant building’ varies in England, Scotland, Wales and Northern Ireland. Links to the definition of ‘relevant building’ for each country can be found below:
  • England - Regulation 7(4) of the Building Regulations 2010
  • Scotland - Regulation 8(6) of the Building (Scotland) Regulations 2004
  • Wales - Regulation 7(4) of the Building Regulations 2010
  • Northern Ireland - Regulation 6(2) of the Building (Amendment) Regulations (Northern Ireland) 2022
  
  In each UK nation, statutory guidance in Approved Document B (England and Wales), Technical Handbook B (Scotland) and Technical Booklet E (Northern Ireland) sets out routes to compliance with the building regulations, including requirements around the Euroclass classification of products depending on their exact use.
  
  As mineral wool insulation achieves a Euroclass Reaction to Fire classification of either A1 or A2-s1, d0, it meets the most stringent requirements of statutory guidance on fire safety with regards to its reaction to fire performance.;