Description, performance and properties

Standards and approvals
British Standards: BS EN 13162:2001
Thermal insulation products for buildings – Factory made mineral wool products – specification

Density
The nominal blown density of the product is 30kg/m3

Thermal Conductivity
Rockwool will not react with any metal components in the loft, nor will it cause loss of plasticizer from PVC cables and pipes (see electrical cable notes).

Durability

Rockwool Blown Loft Insulation is a durable material.  When installed, it will not be afftected by normal ventilation within the loft space and will remain as an effective loft insulation for the life of the building.

Electrical Cables
The TEE wiring regulations, BS.7671:1992 and the current edition of the Electricians Handbook, give guidance on the correction factors to be applied in down rating cables according to the situation.  Each case should be calculated separately.

Loft Hatches
Covers to loft hatches should be insulated with a minimum thickness of 100mm Rockwool Rooll.  To prevent disturbance of the blown insulation when gaining access and leaving loft space, a Rockwool cardboard ‘hatch box’ is fitted around the joist/trimmers.

U Values

Tiled pitched roof, 100mmRockwool Blown Loft insulation between joists
(with the additional thickness of Rockwool Blown Loft insulation over joists)

Acoustic Performance
Rockwool Blown Loft Insulation can improve the sound insulation of a building.  250mm of Rockwool Blown Loft Insulation, with an isolated 12.5mm plasterboard ceiling, achieved > 50dB reduction in a tiled roof construction.

Fire classification
Rockwool Blown Loft Insulation achieves a reaction fo fire classification of A1 as defined in BS EN 1350-1.

Design Details
It is essential that the Rockwool Blown Loft Insulation does not block the ventilation path from the eaves.  It is also desirable that the loft insulation links to the wall insulation.  The method of obtaining these two requirements will vary depending on building design and whether it is new-built or refurbishment.  The following suggestions are for guidance only and each individual building will require separate assessment.

New-build: Extend the cavity wall insulation to the underside of proprietary ventilation trays fitted between the rafters.

Refurbishment: Use a ‘stopper’ of Rockwool Roll placed between the wall plate and the underside of the eaves ventilation tray.  This will ensure the required ventilation path is maintained and help reduce cold bridging.

Health and safety
Current HSE ‘CHIP’ Regulations and EU directive 97/69/EC confirm the safety of Rockwool mineral wool; Rockwool fibres are not classified as a possible human carcinogen.

The maximum exposure limit for mineral wool is 5mg/m3 , 8
hour time-weighted average.

A Material Safety Data Sheet is available from the Rockwool Marketing Services Department to assist in the preparation of
risk assessments, as required by the Control of Substances Hazardous to Health Regulations (COSHH).

Environment
Rockwool insulation relies on entrapped air for its thermal properties; air is not a VOC and it does not have Global Warming Potential (GWP) or Ozone Depleting Potential (ODP).