Frequently asked questions

Answers

  • Can a composite panel with rock wool core and steel faces be recycled?
  • Yes. The steel face can be stripped from the rock wool core. The rock wool can then be returned to the manufacturer and used to make new product. Shredding and recycling of sheets of organic coated steel cladding and roofing is common practice in the UK and the recovered material can be added to the steel furnace.
  • What are Euroclasses?
  • Euroclasses provide a common method for comparing the performance of products in the event of a fire across the European Union.

    Resistance to fire performance shows how materials resist the spread of a fully developed post-flashover fire from the room of origin to an adjacent space. Data may also consider the resistance to collapse of structural elements.

    Reaction to fire performance looks at how materials behave in the early stages of a fire, from ignition to flashover, which involves the entire contents in the room of origin. It considers combustibility, energy available for release, fire growth rates, spread of flame, generation of smoke and the formation of burning droplets or particles.

    Reaction to fire has traditionally been assessed using at least 30 different national standards, many of which give different answers to the question “is this product safe to use in this building?”. To resolve this difference of approach between European countries and provide a harmonized assessment method, new fire test classification procedures, called Euroclasses, were developed in conjunction with new CEN (The European Standardisation body) fire test methods.

    The system classifies products, according to their fire resistance using the designations: A1, A2, B, C, D, E and F. The most fire-retardant products (including rock wool) have been placed in classes A1 and A2, with the fire risk increasing down through the table. A decisive factor in the classification is the time that a product takes to reach flashover. Products in Class A are not subject to flashover at all.
Euroclass Flashover potential Example materials
A1 No Concrete
Brick
Most rock and glass wool
A2 No Plasterboard
Cement particle board
Some rock and glass wool [foil faced]
B No Painted gypsum board
Some fire resistant MDF
Some birch plywood
C Yes
10-20 minutes 		Most fire resistant MDF
Some European plywood
Phenolic foam[foil faced]
D Yes
2-10 minutes 		Expanded polystyrene type A
Polyisocyanurate foam [foil faced]
Extruded polystyrene
Vinyl wall coverings [gravure print]
E Yes
< 2 minutes 		Polyisocyanurate foam [sprayed]
Wood fibre board
F Yes
Early failure 		Expanded polystyrene type N

Note: Check with individual product manufacturers for specific product specifications.

  • What is Non-combustibility?
  • The simple definition of non-combustible is ‘not capable of igniting and burning’ but this gets a little more complicated when fire engineers become involved.

    The development of a building fire depends on many factors, including where and how the fire starts, whether there are fire protection systems and very importantly - what combustible material is available to feed the fire.
  • What is Reaction to fire performance?
  • How materials behave in the early stages of a fire, from ignition to flashover is vital and this is referred to as Reaction to Fire performance. It considers combustibility, energy available for release, fire growth rates, spread of flame, generation of smoke and the formation of burning droplets or particles. One of the most important issues of reaction to fire performance is the potential for flashover to occur – the spontaneous ignition of hot smoke and gases - which can lead to a fire spreading uncontrollably

    Non-combustible materials do not support combustion, nor release hot smoke and flammable gases.
  • What is the test for non-combustibility?
  • Rock wool can be classed as non-combustible when tested to BS EN ISO 1182, a reaction to fire test for building products. This test identifies products that will not contribute significantly to a fire, regardless of their end use.
  • In a fire is flame or smoke more dangerous?
  • Of the numerous ways by which fire can kill, flames are the least likely cause. Toxic gases in smoke and hot air from burning materials damaging lungs are the most common causes of death and injury. The sure way to limit this risk is to only use non-combustible materials.
  • Does plastic foam have to be burning to produce toxic smoke and gases?
  • It is important to realise that toxic gases and smoke are not just produced by fully ignited materials. When combustible materials such as PIR are exposed to flames or heated they may char and produce pyrolysis gases, the gases that cause flashover, prior to full ignition. At this stage toxic gases may be invisible and at higher concentrations then when the material is obviously burning with smoke and flames.
  • Is toxic smoke a danger from all burning organic materials?
  • All organic materials such as plastic foam insulation, evolve toxic decomposition products when burning. Of the toxic smoke products, carbon monoxide [CO] is recognised as the main toxicant in fires. Hydrogen cyanide [HCN], elevated level of carbon dioxide [CO²] and reduced oxygen are also important in their contribution to the asphyxiating characteristics of smoke gases. There are other components in smoke gases that cause sensory irritation to eyes and the upper respiratory tract. These compounds include acid gases produced from the combustion of halogen containing materials [where hydrogen chloride, HCl, is the most common].
  • Are building materials tested to find out what toxic gases are produced when the material burns?
  • Unfortunately in the UK the answer is no. Tests look at the reaction to fire of building materials — but if the sample burns and produces smoke there is no measure of the presence and concentration of any toxic gases in the smoke. There are few mandatory standards that address the toxicity of smoke gases. This obviously varies between countries and regions, however as an example, the European fire classification system for construction products [Euroclasses] does not include any requirement on combustion toxicity.
  • Why is mineral wool insulation ideal for noise absorbing?
  • A Mineral wool insulation has an open fibrous structure making it ideal for absorbing and regulating noise.
Critical health effects from noise graph
  • What's a good sound environment?
  • A Noise should be dampened to such an extent that it no longer interferes with the activity you were set out to do. Just 30 dB(A) is disturbing to sleep. Noise with sound levels of 35 dB(A) or more interferes with the intelligibility of speech in smaller rooms.

    A 10 dB difference is perceived by the human ear as a doubling (or halving) of the audible sound.
  • Is there any cancer risk from the fibres of rock wool?
  • The International Agency for Research on Cancer (IARC) — part of the World Health Organisation — in October 2001 carried out a review of man-made vitreous fibres concluded that mineral wool insulation was "… unclassifiable as to its carcinogenicity to humans".

    The safety of mineral wool insulation fibres is now beyond doubt and mineral wool insulation fibres should be cleared of any suspicion of carcinogenic effect, and removed from IARC’s list of suspected carcinogenic agents.
  • The EU is focusing more on the safety of chemicals and building materials. What is their view on the safety of mineral wool?

  • A The Directive 97/69/EEC is the way that the EU looks at the carcinogenic potential of all substances and materials. Rock wool meets or exceeds requirements for safety so is not classified as a carcinogen in any way in the EU.

    Please click here if you wish to link to the Directive EU Directive 97/69/EEC
  • What is the Regulatory Reform [Fire Safety] Order?
  • The RRFSO is the biggest overhaul of fire safety legislation in decades. It applies to England, Wales and Northern Ireland. There is similar legislation in Scotland. The Government’s over-riding aim is to save more people from death and injury by reducing risk and preventing fires. Key to this is a switch from fire protection to fire prevention and the foundation to this is a new emphasis on fire risk assessment. Changes to Part B of the Building Regulations reflect this and for the first time designers are being asked to complete a fire risk assessment as the first stage of the design process. The revised Construction Design and Management Regulations [CDM] that will came into effect in April 2007 gives more detail to this approach.
  • What guidance does the RRFSO give when it comes to insulated steel faced panels?
  • The changes in the legislation underline the new fire prevention approach which asks designers to identify fire risks at an early stage and try to remove them. An example would be to remove all combustible materials from areas of risk.

    The RRFSO has recognised the risks associated with non-combustible panels. It states, “The potential for fire development involving mineral fibre cores is less than that for panels containing polymeric cores. Therefore, in areas where this is considerable life risk, it may be appropriate to consider replacing combustible panels.”
  • What is a fire risk assessment?
  • The fire risk assessment is a structured assessment of the fire risk in the building for the purpose of expressing the current level of fire risk, determining the adequacy of existing fire precautions and determining the need for, and nature of, any additional fire precautions.

    The approach to fire risk assessment introduced by the government in the recent RR FSO tends to parallel that adopted in health and safety risk assessments, whereby the objective of the risk assessment is not limited to merely preventing harm to people as a result of a hazard, but tries to eliminate or reduce the hazard itself. Thus, the fire risk assessment begins with efforts to reduce the likelihood of fire.
  • How far can a fire risk assessment work?
  • The likelihood of fire can, never be reduced to zero. Accordingly, there is normally a need for fire protection measures contained in Building Regulations such as means of escape, measures that assist in the use of escape routes, means of giving warning of fire and means for fighting fire. However, fire protection measures, by definition, only have a bearing on fire safety after fire has occurred and, therefore, fire prevention has failed.

    Fire prevention measures, fire protection measures and fire safety management can be considered as variables, the standard of which can be reduced or increased, according to the fire risk.

    However, some factors that have major impact on fire risk are not variable, but are "given" factors for the building in question. Such factors include:
  • The height of the building [e.g. single storey or multi-storey, low rise or high rise, the presence of basements]
  • the construction of the building [e.g. largely non-combustible or mainly combustible]
  • The complexity of the building and the floor area of each floor
  • The activities and processes carried out in the building [e.g. handling of highly flammable materials, creation of combustible wastes, use of ignition sources]
  • The history of fires in the building

Although the above factors cannot (or cannot readily) be changed, their effect on fire risk needs to be taken into account in the fire risk assessment, so that they are reflected in the level of fire risk expressed in the fire risk assessment.