SBI Testing Programme

Transcription

1 Reaction to fire behaviour SBI Testing Programme Single Burning Item (pren13823 final draft September ) Mounting and Fixing conditions for EPS boards Xavier ALLANIC KNAUF CRD Date of Publication : 24/2/4 SUMMARY This report, requested by EUMEPS, concerns the reaction to fire performance of naked EPS board when tested in the SBI. The aim of the testing programme is to evaluate the effect of mounting and fixing conditions of EPS in the SBI apparatus. The influence of the nature of the substrate (calcium silicate, gypsum plasterboard, fibre cement) and the presence/absence of an air gap (no gap, 25mm, mm) between the test specimen and the backing board are studied. The study demonstrates that both parameters (substrate and gap) influence the reaction to fire behaviour of EPS specimen (mechanically fixed). The standardised mounting (without air gap) is the preferred option since the presence of an air gap has only a minor effect on the test result and classifications but impairs the repeatability of the results and does not simplify the mounting operations. In the first part of the study, the maximum available upper Euroclasses (B) can be achieved (for the EPS sample tested) by using a particular substrate (fibre cement board). Complementary tests carried out with the standard fibre cement board (EN 13238) did not confirm this finding. The use of gypsum plasterboard as substrate would enhance the field of application of a test result because it has a lower density than standard substrates such as calcium silicate and fibre cement board and hence, covers a wider field of substrate densities. Furthermore, the testing cost would be dramatically reduced because standard gypsum plasterboard is almost times cheaper than calcium silicate boards. EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 1 of 19

2 Introduction This report concerns the reaction to fire performance of naked expanded polystyrene (EPS) board. The testing programme has been requested and defined by the association of European Manufacturers of EPS (EUMEPS) and the tests have been carried out at the SBI Laboratory of KNAUF in France. The harmonised European standards for reaction to fire tests are now accepted and published. They were up to finalisation at the beginning of the study. Among them the Single Burning Item method still causes concern to the Industry, as the influence of certain parameters is not well known. The aim of this testing programme is to evaluate the effect of mounting and fixing (M&F) conditions of EPS in the SBI apparatus. The objective is to determine a precise definition of these conditions so as to achieve a robust and reliable Euro classification. The other objectives of the programme are: simplification of the test procedure, optimum field of extended application, reduction of testing costs. The tests have been done according to the procedure described in pren13823 (rev. Sept. ), i.e. the product specimen is exposed during min to a burner that produces 3kW with the following test steps: s start of test 1s ignition of the auxiliary burner, 3s ignition of the main burner (the flame attacks the product), 15s end, stop of the burner, 1s end of the data recording. In principle two test per product (EPS + mounting condition) have been carried out. In some cases 3 or 4 tests were done. EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 2 of 19

3 1. Material The product tested is a mm, kg/m 3 EPS-FR (BASF Styropor F-315) board with dimension of 5* mm cut from blocks moulded at KNAUF CRD. After a one-week conditioning period at 7 C, the samples were ready for testing. The M1 quality of the product has also been controlled. In the complementary test a thicker specimen (1mm) of the same product is used. 2. Mounting & Fixing Each test specimen was made of 5 boards of EPS in order to cover the dimension (15* and 15*495 mm) of a SBI specimen. They were all fixed mechanically (screws + washer) to the substrate. The mounting is described in the Figure 1. The sides of the long and short wing were not (partly) closed but as prescribed in the test method. Short Long Wing Long Short Wing Legend 1 : Long Wing : EPS dimensions 15 ± 5 mm x ± 5 mm 2 : Short Wing : EPS dimensions 15 ± 5 mm x 495 ± 5 mm 3 : Substrate/Backing Board 4 : Screws + washer Figure 1: Mounting of the EPS panels The testing programme was divided into two parts. First, the main programme studied the influence of the following parameters : Nature of the substrate: Standard substrate (Calcium Silicate Board), thickness: 12.5 mm, density: kg/m³ (conform EN13238) Fibre Cement board, thickness: 12.3 mm, density: 1 kg/m³ BA13 (standard Gypsum Plaster board), thickness: 12.5 mm, density: 73 kg/m³ (conform EN13238) EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 3 of 19

4 Presence/Absence of an air gap between backing board and specimen: Standard mounting with no ( or infinite) gap : the specimen is fixed to the substrate acting as backing board), 25-mm gap (the specimen is fixed to the substrate, a 25 mm frame is placed between the substrate and the standard backing board (Calcium Silicate board), -mm gap (the specimen is fixed to the substrate, a mm frame is placed between the substrate and the standard backing board (Calcium Silicate board). The various combinations of tests parameters tested were: Standard Mounting (No gap) 25 mm gap mm gap Calcium silicate X X Fibre cement X X X Gypsum Plasterboard X X X Table 1 M&F conditions tested In the complementary test series two additional substrates were evaluated : standard substrate fibre cement board : thickness 6mm, densities 1kg/m3 (conform to EN13238). standard non FR particle board : thickness 12 mm, density 7kg/m3 (conform to EN13238). EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 4 of 19

5 3. Results 3.1 Overall behaviour of EPS-FR at SBI The overall behaviour of EPS-FR samples to the flames is constant with the various mounting and fixing conditions. On Photo 1 EPS has shrunk away from the burner zone. In no case flames have spread along the specimen. The damaged zone corresponds only to molten EPS. The specimens never ignited. Photo 1: EPS-FR specimen in SBI at ~9minutes Photo 2: EPS-FR specimen in SBI at the end of the test A pool of molten EPS is present in the bottom corner of the U profile. This pool is heated by the radiation of the burner and ignited. The time of ignition of this pool depends on the mounting and fixing conditions. The later it ignites, the lower is the RHR value. At the end of the test (photo 2) most of the specimen is molten. No burning droplets or particles fell from the specimen into the droplets zone. Some molten EPS ignites when falling along the substrate. But this is not flaming droplets as explained in the SBI standard. As a consequence, the droplets classification is always d. The lateral flame spread (LFS) is not larger than the burner zone. The length of the otherwise damaged area is 75mm on the long wing. In all cases the THR parameter is very close to the upper class limit. The limiting parameter for fire is the FIGRA. For smoke, the SMOGRA gives always Euroclass s2 but the TSP index is also important. EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 5 of 19

6 3.2 Main testing programme Calcium Silicate substrate, standard mounting The same test has been carried out as done for a previous EUMEPS testing program in As a consequence, only one test has been carried out this time, just to be sure that the result is the same. The table below indicates the values of the main parameters for Euro classification (see Annex). The behaviour of EPS in this condition is very similar to what was observed in 1997 (Ref. 1). The reason for the difference in intermediate class for the THR parameter is that the values are very close: the Class C/D limit is 15 MJ. The graph indicates the average evolution of the RHR during the test. At the time ~4 seconds (4min 3 after ignition of the main burner) the RHR presents a peak. During the test the ignition of the pool of molten EPS at the bottom of the specimen occurred around this time. The classification for this M&F condition is D s3 d. Figure 1: Test results Calcium Silicate/Standard Mounting EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 6 of 19

7 3.2.2 Calcium Silicate substrate + gap 25mm The presence of the gap does not increase the time of ignition of the molten EPS pool (~4 s). But it reduces the RHR peak to kw instead of kw without the simulated air gap. The values of the fire and smoke index are lower than with the standard mounting but the classification is the same. The classification for this M&F condition is D s3 do. 1 1 Test 1 Test 2 Mean 1 RHR (kw) Time (s) Figure 2: Test results Calcium Silicate/Gap 25mm EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 7 of 19

8 3.2.3 BA 13 substrate, standard mounting The behaviour of the specimen and the values of the parameters are very similar to those of the one obtained with Calcium Silicate substrate (cf ). This indicates that it would be possible to use Gypsum plasterboard instead of Calcium Silicate board as substrate for testing EPS in SBI. This would reduce the testing costs possibly by a factor of. The classification for this M&F condition is D s3 d Test 1 Test 2 Mean RHR (kw) Time (s) Figure 3: Test results BA13/Standard Mounting EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 8 of 19

9 3.2.4 BA13 substrate + gap 25 mm As observed with the gap when using Calcium Silicate substrate (cf ), the presence of a gap in this M&F condition does reduce the FIGRA and THR values. But here the 2 tests give quite different results. It is difficult to understand whether this is due to the gap or to the low repeatability of the SBI method. The additional gap of 25mm does not influence the classification obtained. The classification for this M&F condition is D s3 d Test 1 Test 2 Mean RHR (kw) Time (s) Figure 4: Test results BA13/Gap 25mm EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 9 of 19

10 3.2.5 BA13 substrate + gap mm The important difference in the results between the 2 tests is even larger than found with the 25 mm air gap (cf ). This difference appears mainly with the fire parameters (FIGRA and THR). Classification C s3 d was obtained in the first test: the FIGRA is just under the class C limit (25 kw). The second test gives approximately the same results as obtained with the standard mounting. It appears that a simulated air gap does not modify significantly the classification but it reduces the repeatability of the method. The classification for this M&F condition is D s3 d Test 1 Test 2 Mean RHR (kw) Time (s) Figure 5: Test results BA13/Gap mm EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 1 of 19

11 3.2.6 Fibre cement board substrate, standard mounting After the first two tests a third test was done to confirm the previous results. The cement board substrate does modify the behaviour of EPS during the test and result in an improved (better) Euroclassification. Molten PS flows much slower than on the 2 other substrates tested. As a consequence the accumulation and ignition of the molten EPS pool is delayed. All parameters, i.e. fire and smoke, demonstrates a better behaviour. The classification for this M&F condition is B s2 d Test 1 Test 2 Test 3 Mean RHR (kw) Time (s) Figure 6: Test results Fibre Cement/Standard Mounting EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 11 of 19

12 3.2.7 Fibre cement board substrate + gap 25mm The behaviour is similar to that found in the previous case (cf ). The influence of the simulated air gap is a limited to a slight increase of all parameter values (mainly for smoke), but not enough to modify the classification. The classification for this M&F condition is B s2 d Test 1 Test 2 Mean RHR (kw) Time (s) Figure 7: Test results Fibre Cement/Gap 25mm EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 12 of 19

13 3.2.8 Fibre cement board substrate + gap mm Compared to the test with the 25 mm gap (cf ) the larger gap seems to emphasise the low repeatability of the results. The differences are particularly significant with the smoke parameters. The classification for this M&F condition is B s3 d. 1 RHR (kw) Test 1 Test 2 Mean Time (s) Figure 8: Test results Fibre Cement/Gap mm EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 13 of 19

14 3.2.9 Conclusion of the main study This programme illustrates the large influence of mounting and fixing conditions of EPS specimen in the SBI apparatus. In particular the nature of the substrate on which the specimen is mounted plays an important part in the Euroclasse obtained. It has been demonstrated that the calcium silicate substrate could be replaced by a 12.5mm paper faced gypsum plasterboard. This has no impact on test results (Euroclass D for mm, kg/m3 FR-EPS) but covers more end-use applications because of the lower density of the plaster board than that of the calcium silicate board. Moreover this would reduce the cost of testing due to the low price of 12.5mm paper faced gypsum plasterboards. This testing programme also indicated that higher classifications than Euroclasse D could be achieved using fibre cement board with a density of 1 kg/m3 at a thickness of 12,3mm. EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 14 of 19

15 3.3 Complementary testing programme Introduction Complementary tests have been carried out to check the influence of the thickness of EPS : 1mm EPS specimen were tested. As the fibre cement board used was not fully conform to EN (Conditioning procedures and general rules for selection of substrates), complementary tests have also been carried out with the standard fibre cement substrate in order to compare the results to the previous ones obtained. Finally a wood panel as described in EN13238 has also been tested as substrate Influence of the thickness of the specimen : 2 tests have been done on 1mm thick EPS. As we could expected the heat released during the SBI test is twice that of the mm. FIGRA reach a value of 116 W/s, wich is very close to the limit of Euroclasse B/C (1 W/s). THR reach a value of 1 MJ and consequently the Euroclass is C instead of B. The smoke related figures SMOGRA and TSP are also higher but the difference of smoke production is not proportional to the difference of thickness. The additional smoke classification becomes S3 instead of S2. The table below indicates the avearge test results of and 1mm product tested. The graph illustrates the evolution of the Heat Release Rate (kw) : EPS mm fibre cement EPS 1mm fibre cement Value Class Value Class FIGRA (W/s) 62.3 B B THRs (MJ) 4.79 B 1.1 C SMOGRA (m²/s²) s s2 TSPs (m²) s s3 Euroclassification B s2 d C s3 d HRRav (kw) EPS mm S1 S2 S3 S1 S time (s) time (s) EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 15 of 19

16 3.3.3 Fibre cement board (6mm, 1kg/m3): The first fibre cement board (A) used was 12.5mm, 1 kg/m3 and did not conform to the requirements of EN tests have been carried out on a corresponding standard fibre cement board (B) : 6mm, 1 kg/m3. The classification achieved is lower and both heat and smoke related figures are higher for substrate B compared to those of substrate A. The tests results and HRR evolution are given below : EPS mm substrate A EPS mm substrate B Value Class Value Class FIGRA (W/s) 62.3 B 14.9 B THRs (MJ) 4.79 B 1.1 C SMOGRA (m²/s²) s s2 TSPs (m²) s s3 Euroclassification B s2 d C s3 d S1 S2 S3 75 S1 S3 S2 S time (s) time (s) EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 16 of 19

17 3.3.4 Wood Panel Substrate (12mm) To be complete we have also checked the influence of a wood panel substrate on the EPS Euro classification. Only one test has been done due to the extreme behaviour of the test specimen. As soon as the naked EPS board was attacked by the burner, EPS shrunk away form the flame and melted down (as it was observed in each test). The exposed wood substrate starts to burn after 5 minutes. The temperature rise is so important that we had to early stop the test. Note : Naked EPS should never be tested on wood panel substrates! EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 17 of 19

18 Conclusion First of all this testing programme illustrates the very important influence of mounting and fixing conditions of EPS specimen in the SBI apparatus. Both parameters studied, presence of an air gap and nature of the substrate, may modify the reaction to fire classification of EPS (mechanically fixed). The presence of a simulated air gap affects (impairs) the repeatability of the results without changing the classification obtained. The use of the frame to simulate the gap does not simplify the mounting operation. The standard mounting condition (without air gap) is the preferred M&F option. It has been demonstrated that it is possible to achieve the maximum available upper Euroclass (B) for this EPS board sample by using a particular substrate, viz.: fibre cement board (12.5mm, 1kg/m3) with or without a gap between substrate and the backing board. Further tests carried out with the standard fibre cement board (thickness 6mm, density 1kg/m3) did not confirm this finding, although the classification of EPS boards with a thickness of mm at a density of kg/m3 achieve a Euroclass C s3 d. (Fibre cement board can represent many substrates used in the standard applications of EPS board, e.g. for internal/external wall insulation.) Using standard gypsum plasterboard (12.5 mm) it is possible to extend the application of a test result because standard gypsum plasterboard has a lower density that the standard substrate proposed by the European standard (Calcium Silicate board). As a consequence the results obtained with BA13 board, as substrate, covers more end-use conditions than with Calcium Silicate board. Furthermore, the testing cost could be seriously reduced because standard gypsum plasterboard is almost times cheaper than calcium silicate boards. EPS on woodbased panels should never be evaluated without the end-use application covering. A summary of the mounting and fixing conditions and resulting classifications are given in Table 2. EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 18 of 19

19 Table 2: Summary of classification results (mean) with different substrates and gap widths Substrate Standard Mounting (No gap)* 25mm gap mm gap Calcium silicate (12.5mm, kg/m3) FR EPS g/l, mm Gypsum Plasterboard (12.5mm, 73 kg/m3) FR EPS g/l, mm Fibre cement (12mm - 1kg/m3) FR EPS g/l, mm Fibre cement (12mm - 1kg/m3) FR EPS g/l, 1 mm Fibre cement (6mm - 1kg/m3) FR EPS g/l, mm Particle Board (12mm - kg/m3) FR EPS g/l, mm D s3 d D s3 d - D s3 d D s3 d D s3 d B s2 d B s2 d B s3 d C s3 d - - C s3 d - - Early Stop of Test - - * substrate = backing board References (1) APME EPS Technical Report EPS 1/: Single Burning Item Reaction to fire naked EPS board final version 25/11/. Parameters / Abbreviations used in the report: EPS-R: regular EPS raw material EPS-FR: flame retardant modified EPS THR (MJ): Total Heat Release in the first seconds TSP (m²): Total Smoke Production in the first seconds FIGRA (W/s): Fire growth rate SMOGRA (m²/s²): Smoke growth rate EUMEPS SBI Testing Programme Mounting and Fixing of EPS boards Page 19 of 19