Method Statement for the Fire Risk Assessment of Multilayer Paint Finishes
||Experience gained over a number of years indicates that multiple coatings of paint, applied as a consequence of routine maintenance, can seriously and adversely affect the fire behaviour of wall and ceiling surfaces by reducing the BS 476 Part 7 Surface Spread of Flame performance required by Building Regulations from Class 1 to Class 4. The methodology described is used to assess the degree of fire spread risk presented by such surfaces and thereby provide recommendations as to the action to be taken upon redecoration to reinstate the spread of flame performance rating.
||The assessment methodology used is in accordance with that described in the Department of Environment Research Report No. 39/3/204. This involves visual survey, site testing and laboratory microscopic analysis of representative paint specimens.
The nature and condition of the paintwork at the site will be observed and reported together with a general description of the premises.
Two types of tests will be conducted on site: Adhesion Tests and Blister Tests.
The Adhesion Test evaluates the susceptibility of the paint layers to delamination both from the substrate and each other. A line is cut through the paint finish to the substrate. The point of the knife is inserted and pushed horizontally across the surface to enable the paint to chip. The substrate is not penetrated. The extent and nature of the delamination are noted.
The Blister Test evaluates the behaviour of the paint finish under the influence of heat. A high temperature hot air gun is directed at the paint finish without direct flame impingement. The temperature of the area is monitored and the occurrence and nature of any blistering are noted.
Paint specimens will be taken at the time of survey for subsequent microscopic analysis in the laboratory. The examination evaluates the number, colour, thickness and type of the constituent paint layers thereby providing an indication of the combustible content of the finish.
||Unless otherwise agreed with the sponsor, specimens will be selected from all the enclosed communal areas at the site. These will include internal staircases and corridors. Any painted surface that it is considered could contribute to potentially hazardous flame spread will be tested. This will include walls and ceilings. The number and location of the tested positions will be selected to be fully representative of the risks at the site. Typically, on average, between one and two positions will be tested per floor with a minimum of six samples taken per site.
|4.||Fire Risk Assessment
||The assessment will be made on the basis of the test and analysis results obtained. Expert opinion will be offered both as to the risks present and, where relevant, what measures need to be taken to attain a satisfactory flame spread. In general one of four actions will be recommended. On surfaces found to present a high risk and where there is poor adhesion, chemical stripping will be proposed. For high risk surfaces where adhesion is satisfactory, 'upgrade' coatings will be proposed. For risks where there is a moderate paint thickness with good adhesion, overcoating with flame-retardant paint will be recommended. Finally, the assessment may conclude that the fire risk is low, in which case 'standard' products can be used in overpainting.
||Full details of the survey, test results and assessment will be given in a confidential, written report. It will include conclusions and recommendations together with any other advice or information as may have been agreed with the sponsor in advance. Micrographic images will only be included on prior request. Paint samples will be retained for at least twelve months after issue of the report.
||All tests and assessments will be undertaken only by professionally qualified, Chartered Engineers holding corporate membership of the Institution of Fire Engineers and having relevant experience in the reaction to fire behaviour of materials.