Caution on roof insulation fire ratings

Rigid PIC foam board insulation showed no ignition throughout the Firelab testWhile the new SANS 428 fire regulations, as part of the National Building Regulations, have been welcomed as a major step forward with regard to the testing, evaluation and recommendation of roof insulation materials, D&D Roof Insulation has highlighted a critical shortcoming with the new fire rating system.

The new standard for the evaluation of roof insulation liners comprises various numbered parts which make up the total test protocol procedure. The most important of these is the Part 11 large scale test done at Firelab, with and without sprinkler systems. The test involves the test roof insulation liner being installed, as it is in practice, but in a scientifically controlled environment. The test simulates a scenario where the fire starts small and grows up to roof height.

The completed evaluation of the test product is then rated according to the SANS 428 classification table, in which one of the classifications is Surface Fire Properties. This relates to the flame spread of the material under the test conditions, with 1 being the best (no flame spread) and 6 being the worst (rapid flame spread).

Another aspect of the rating is combustibility, with an ‘A’ classification for non-combustible and a ‘B’ classification for combustible materials. A product would achieve an A1 rating if it did not ignite even in the Part 11 test.

There is however a major shortcoming in the final ratings of roof insulation products.

In June last year, the Part 5 combustibility test parameters were changed in line with international standards, such that even the products previously ‘A’ rated are now ‘B’ rated. D&D Roof Insulation points out that this change was made without due consideration for the effect it would have on the final ratings of materials within the parameters of the SANS 428 test protocol.

The Part 5 combustibility test is done in an electrically heated furnace pre-set at 750°C and the test sample, to be considered non-combustible, should not increase the furnace temperature by more than 50°C or support flaming for more than five seconds.

The fire source in the large scale Part 11 test peaks at around 550°C and any combustible roof insulation material, installed as in practice, will ignite at this temperature. The problem is that products that did not ignite at this temperature at all, as opposed to those that did in the Part 11 test, are all now assigned the same fire rating.

Considering that tin will melt at 233°C, aluminium at 660°C, and steel alloys at around 1 370°C, it is clear that all commercially rated roof insulation materials will be literally obliterated in seconds at 750°C, in the Part 5 test used to rate products’ combustibility.

TIASA – the Thermal Insulation Association of Southern Africa – has taken up this concern with the SABS fire committee and has requested a review of the Surface Flame Spread ratings of roof insulation liners. The review is pending, awaiting the completion of relevant research.

Professionals and contractors are therefore advised to scrutinise SANS 428 test reports of various roof insulation materials closely, before deciding on which product best suits the given application.

ceiling insulation fire ratings on roof insulation fire regulations fire resistance classifications fire testing of roof insulation resistance to combustibility resistance to spread of flame roof insulation materials SABS SANS SANS 428 thermal insulation
Previous story
keyboard_arrow_upPVC strip curtains suit diverse applications
keyboard_arrow_downPVC strip curtains suit diverse applications

According to Wim Dessing, managing director of Apex Strip Curtains and Doors, high quality PVC strip curtains offer an affordable solution in various applications where dirt, dust or insects need to be kept out and hygiene, humidity, temperature and noise need to be controlled. "Our Balledge PVC strip curtains are equally at home in the food, pharmaceutical and heavy engineering industries," says Dessing.

Next story
keyboard_arrow_upKhanda Seating caters for maximum capacity in church
keyboard_arrow_downKhanda Seating caters for maximum capacity in church

Khanda Seating, manufacturer of a variety of seating options for stadiums, auditoriums and other large venues, recently completed the installation of seating at the new Universal Church of the Kingdom of God in Johannesburg. The church will accommodate a maximum attendance of 7 500 people on Khanda's Rhema seats.

keyboard_arrow_upITC-SA to host CPD-accredited timber conference at Interbuild Africa
keyboard_arrow_downITC-SA to host CPD-accredited timber conference at Interbuild Africa

The Institute for Timber Construction South Africa (ITC-SA), SAQA-accredited professional body and watchdog for the timber construction industry in South Africa, will be hosting a CPD-accredited timber construction conference on the 16th of August at Expo Centre Nasrec as part of the upcoming Interbuild Africa 2018.

keyboard_arrow_upDrywall installation augments hospital fit-out
keyboard_arrow_downDrywall installation augments hospital fit-out

Saint-Gobain Gyproc was contracted to stipulate product and fit-out specifications for the interior construction of the recently relocated Netcare Christiaan Barnard Memorial Hospital.

keyboard_arrow_upCPD-accredited roof inspector training to boost skills in the construction industry
keyboard_arrow_downCPD-accredited roof inspector training to boost skills in the construction industry

The Institute for Timber Construction South Africa (ITC-SA), the professional body for the engineered timber construction sector, will be hosting a CPD-accredited Roof Inspector Training Course at its head office in Isando from 28-30 August 2018.