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Health and Safety Executive

Preliminary fire testing of composite offshore pedestrian gratings

Prepared by the Health and Safety Laboratory for the Health and Safety Executive

RR950 Research Report



Burrell G, Jagger S, Johnson D Harpur Hill Buxton Derbyshire SK17 9JN

Fibre Reinforced Plastic (FRP) gratings can offer a number of attractive advantages over traditional steel gratings such as enhanced environmental resistance, reduced through life costs and the promise of significant mass savings. However, this preliminary study has demonstrated that the current fire certification of FRP gratings by a standardised (ASTM E119 cellulosic fire) time-temperature curve is not representative of the temperature profile of a hydrocarbon pool fire.

Experimental data suggests that FRP gratings exposed to a hydrocarbon pool fire can pass the fire integrity certification standard to L2 but be structurally impaired such that they are not fit for pedestrian use.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

HSE Books

© Crown copyright 2012

First published 2012

You may reuse this information (not including logos) free of charge in any format or medium, under the terms of the Open Government Licence. To view the licence visit www.nationalarchives.gov.uk/doc/open-government-licence/, write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email [email protected].

Some images and illustrations may not be owned by the Crown so cannot be reproduced without permission of the copyright owner. Enquiries should be sent to [email protected].

ii

KEY MESSAGES



1

EXECUTIVE SUMMARY

Fibre reinforced plastic (FRP) is increasingly considered for a range of applications in the offshore oil and gas sector. In comparison to traditional engineering materials such as steel, FRP can offer a number of attractive benefits such as enhanced environmental resistance, reduced through life costs and the promise of significant mass savings. These perceived benefits are exemplified by FRP gratings which are increasingly commonplace on installations within the UK Continental Shelf (UKCS).

Performance requirements for FRP gratings in a marine environment are detailed within a U.S. Coast Guard memorandum entitled, Policy File Memorandum on the use of fiber reinforced plastic (FRP) gratings and cable trays (PFM 2-98). FRP gratings must satisfy structural fire integrity, fire retardance, flame spread and smoke generation requirements. A fundamental element of the qualification procedure is that the gratings must be exposed to a standardised time-temperature curve for a cellulosic fire (ASTM E-119) for a period of 60 minutes.

However, in offshore oil and gas operations the likely source of fire will be in the form of a hydrocarbon pool which is recognised to be more severe than a cellulosic fire. Accordingly, the Health and Safety Executive (HSE) requested that the Health and Safety Laboratory (HSL) perform a series of preliminary experiments to gauge the performance of a range of FRP gratings under such conditions.

The principle findings of the study were:

1. As part of its qualification requirements for structural fire integrity gratings, the US Coast Guard specifies that sample gratings are tested in a furnace and exposed to a standardised time-temperature curve for a cellulosic fire (ASTM E-119). The exposure time is 60 minutes rising to a final temperature of 927 °C. The temperature data obtained as part of this study demonstrate that this time-temperature profile is not representative of a hydrocarbon pool fire scenario, which can reach this temperature in 5 minutes. Therefore the results may be misinterpreted to give a false sense of confidence that the gratings can support loads for longer than they can in an actual hydrocarbon pool fire.

2. When exposed to a hydrocarbon pool fire, loaded and unloaded isopthalic polyester gratings fail after 1.5 minutes and 5.5 minutes respectively.

3. When exposed to a hydrocarbon pool fire, loaded glass reinforced phenolic gratings (qualified as structural fire integrity level 2) deform, thereby shedding their load within 6 minutes.

4. When exposed to a hydrocarbon pool fire of approximately 15-17 minutes duration, the structural integrity of loaded and unloaded reinforced phenolic gratings (qualified as structural fire integrity L2) appears to be compromised. Despite this, all of the surviving gratings met the post-loaded test criteria for qualification as L2 according to PFM 2-98.

5. When exposed to a hydrocarbon pool fire of approximately 15-17 minutes duration, glass reinforced phenolic gratings (qualified as structural fire integrity L2) failed when subjected to the dynamic loads applied as a consequence of a 90 kg male running over them despite passing the post-loaded test criteria for qualification as L2 according to PFM 2-98.

2

6. Further work is necessary to understand fully the behaviour of composite gratings in a fire and develop a rigorous and robust test procedure for ensuring they are fit for installation offshore.

3

CONTENTS PAGE

1. INTRODUCTION ........................................................................ 5 1.1 BACKGROUND 5 1.2 AIMS 6

2. METHODOLOGY ....................................................................... 7 2.1 GRATINGS 7 2.2 FIRE TESTING 8 2.3 POST FIRE EVALUATION 10

3. RESULTS................................................................................. 12 3.1 FIRE TESTING 12 3.2 POST FIRE EVALUATION 15

4. DISCUSSION ........................................................................... 19

5. CONCLUSIONS ....................................................................... 20

6. REFERENCES ......................................................................... 21

APPENDIX A.................................................................................. 22

APPENDIX B.................................................................................. 23

APPENDIX C.................................................................................. 27

APPENDIX D.................................................................................. 49

4

1.1

1. INTRODUCTION

BACKGROUND

Fibre reinforced plastic (FRP) is increasingly considered for a range of applications in the offshore oil and gas sector. In comparison to traditional engineering materials such as steel, FRP can offer a number of attractive benefits such as enhanced environmental resistance, reduced through life costs and the promise of significant mass savings. These perceived benefits are exemplified by FRP gratings which are increasingly commonplace on installations within the UK Continental Shelf (UKCS).

Whilst it is clear that FRP gratings can offer a host of perceived benefits, one area of concern is their performance at elevated temperatures and in fire scenarios. In 1998 the United States Coast Guard (USCG) produced a policy file memorandum on the use of FRP Gratings and Cable Trays, PFM 2-98 (U.S. Department of Transportation, 1998). Therein, it is stated that “…these materials are typically combustible and exhibit mechanical properties different from steel and thus require careful consideration with respect to fire integrity, combustibility and smoke generation”. Accordingly, PFM 2-98 sets out fire test requirements in terms of structural fire integrity, fire retardance, flame spread and smoke generation.

Structural fire integrity performance is measured by way of a series of test procedures as detailed in Appendix A. Qualification of the grating to Level 1, Level 2, or Level 3 is based on successfully fulfilling the appropriate testing requirements. FRP gratings are currently available that satisfy the Structural Fire Integrity Level 2 (L2) and Level 3 (L3) requirements.

The intended performance levels are described in PFM 2-98.

“(a) Level 1 (L1): FRP gratings meeting the L1 performance criteria are intended to be satisfactory for use in escape routes or access for firefighting, emergency operation or rescue, after having been exposed to a significant hydrocarbon or cellulosic fire incident. In addition they are also acceptable for the services and functions described for levels L2 and L3.

(b) Level 2 (L2): FRP gratings meeting the L2 performance criteria are intended to be satisfactory for use in open deck areas where groups of people are likely to assemble such as temporary safe refuge or lifeboat embarkation areas. In addition they are also acceptable for the services and functions described for level L3.

(c) Level 3 (L3): FRP gratings meeting the L3 performance criteria are intended to be satisfactory for use in egress routes and any areas that may require access for firefighting, rescue or emergency operations during exposure to or shortly after exposure to a transitory hydrocarbon or cellulosic fire.”

A fundamental element of this qualification approach is that gratings are subjected to a standardised time-temperature curve for a cellulosic fire (ASTM E-119) for a period of 60 minutes. In a major hazard scenario offshore it is likely that the fire threat will come from a hydrocarbon pool fire or hydrocarbon jet fire rather than the cellulosic fire simulated by ASTM E-119. Given the expected differences in the time-temperature curve for a hydrocarbon pool fire, the Health and Safety Executive (HSE) requested that the Health and Safety Laboratory (HSL) perform a series of preliminary experiments to gauge the performance of FRP gratings under such conditions.

5

1.2 AIMS

The aim of this preliminary study was to expose loaded and unloaded FRP grating samples to a hydrocarbon pool fire to establish their performance and condition during and after exposure.

It should be noted that it was not the purpose of this experimental phase to conduct an exhaustive testing regime on all grating types and loading scenarios. Rather, a small number of experiments were conducted to gain a basic appreciation of performance such that a more detailed study could be conducted in the future if deemed appropriate.

6

2. METHODOLOGY

2.1 GRATINGS

FRP gratings were sourced from two manufacturers that shall be referred to herein as Manufacturer A and Manufacturer B. A steel grating suitable for offshore usage was also sourced as a baseline. Table 2-1 provides basic data for the various gratings used as part of this study.

Table 2-1: Specifications of grating test specimens

Design Width of I-beam (mm)

Gap between I-beams (mm)

Height of I-beam (mm)

Length between cross braces (mm)

Manufacturer A Glass reinforced phenolic (60% open area)

I-beam 15 23 38 152

Manufacturer B Glass reinforced phenolic (60% open area)

I-beam 15 23 38 152

Manufacturer A Glass reinforced isophthalic Polyester (60% open area)

I-beam 15 23 38 152

Manufacturer A Glass reinforced phenolic (48% open area)

I-beam 15 13 38 152

(note: steel sample measured using vernier calliper)

Load bearing bar centres (mm)

Transverse bar centres (mm)

Height of bearing bar (mm)

Thickness of bearing bar (mm)

Steel 41 100 35 5

Both Manufacturer A’s and Manufacturer B’s glass reinforced phenolic gratings satisfy the Structural Fire Integrity L2 requirements and have secured approval from the USCG demonstrating this achievement. The glass reinforced isophthalic polyester gratings do not satisfy the USCG performance requirements in this regard.

Each of the gratings were cut such that they were approximately 1200 mm long and a minimum of 280 mm wide (Appendix B)(shown in Figure 2-1).

7

2.2

Figure 2-1: Gratings prior to test

FIRE TESTING

PFM 2-98 stipulates that gratings be exposed to the time-temperature curve specified in ASTM E-119 for a period of 60 minutes. The main focus of the current study was to expose the grating specimens to a hydrocarbon pool fire. Accordingly, the experimental setup was in general accordance with that specified within PFM 2-98, the primary variables being the fire exposure and the number of specimens used for testing purposesa.

All of the grating specimens detailed in Section 2.1 were suspended over a pool tray at a height of 480 mm above the water pool surface, supported on two hollow square section steel beams, approximately 80 mm wide, and with a separation of 1000 mm. These were in turn supported on thermolite block pillars as depicted in Figures 2-2 and 2-3.

Where applicable, sand filled metal boxes with a mass of 40 kg and a foot profile of 300 mm by 300 mm were placed on the samples midway across the unsupported span in accordance with PFM 2-98.

Each sample was instrumented with a thermocoupleb, secured with a metal cable tie between the I-beams at the midpoint of the height, width and span of the sample. The measurements of these thermocouples were logged every second. The pool fire was ignited electrically using a hot wire, embedded in a shredded wood wool bundle, soaked in hexane. Each test was recorded using two video cameras located in different positions around the experiment.

a Given the preliminary nature of this study. b K-type, short term range -80 – 1,350 °C

8

1000 mm

480 mm

1500 mm

3000 mm

Figure 2-2: Experimental test setup

Kerosene fuel was pumped into the fire tray using an underwater pipe at a rate of 20 l/min for 2 minutes prior to ignition and this rate was sustained throughout the testing period.

After the failure of both loaded samples within a few minutes, it was decided to prematurely suspend the tests so the fuel pump was stopped 12 minutes from ignition, allowing the pool fire to burn out in approximately 15-17 minutes. As the fire was burning out, the cross braces on one of the unloaded samples failed and it broke into strands.

Three fire tests were conducted in total and the associated details for each test can be found in Appendix C.

Figure 2-3: Experimental setup showing two unloaded and two loaded gratings.

9

2.3 POST FIRE EVALUATION

2.3.1 Post fire visual examination

After the gratings detailed in Section 2.2 had cooled they were removed from the test area and a basic visual examination was performed. A photographic record of the post fire condition of each grating was taken. In particular, any defects as a result of the exposure were recorded.

2.3.2 Post fire testing

Those gratings that were not loaded during the fire exposure were tested in accordance with the post-loaded test requirements detailed within PFM 2-98, or alternatively, underwent a bespoke dynamic load test.

2.3.2.1 Post-Loaded Testing in accordance with PFM 2-98

The post-loaded testing for satisfying the structural fire integrity Level 2 requirements encompass those required for qualification to Level 3 and in addition, a further load test. In order to qualify for Level 3, the grating must not collapse when a 40 kg mass (as used for the loaded gratings during the fire testing) is placed in the centre span of a simply supported test specimen. In addition, to qualify for Level 2, a second test is performed where the simply supported specimen is gradually loaded in increments placed in such a manner that the loading represents a uniformly distributed load (UDL) across the span of the grating. A sheet of foam was used to help distribute the weight of the blocks evenly. In all cases the span was common with that used in the fire testing, i.e. 1000 mm. A photographic record of the testing was taken. Figure 2-4 demonstrates the two tests as described above.

Figure 2-4: Post loading tests of gratings: Left: 40kg test; Right: UDL test

10

2.3.2.2 Dynamic Testing

In order to determine the post fire dynamic impact performance of the grating samples, an experimental procedure was devised whereby a simply supported grating sample was run across. Common with the fire testing and tests described in Section 2.3.2.1, the span in all cases was 1000 mm. The mass of the male volunteer used for the testing was 90.40 kg1. The direction of travel was such that the foot was parallel to the bearing bars of the grating.

Direction of travel

Figure 2-5: Experimental setup for the dynamic impact tests

The test was performed such that a foot strike would occur at approximately the centre span position. Both photographic and video graphic records of the dynamic testing were taken.

1 This included all personal protective equipment (PPE) deemed appropriate for the activity. 11

3. RESULTS

3.1 FIRE TESTING

A summary of the fire testing conducted is provided below. More detailed information on the tests performed and on particular samples can be found in Appendix C.

3.1.1 Isophthalic Polyester

When exposed to a hydrocarbon pool fire it was found that the loaded and unloaded isophthalic polyester gratings failed 1.5 minutes and 5.5 minutes after ignition. The video of the tests showed small flames emanating from the grating indicating that the isophthalic resin was burning. The loaded grating sagged and fell through the gap between the supporting beams, where it was pinned to the bottom of the fire tray by the metal box. The unloaded isophthalic polyester grating continued to burn until it could no longer support its own weight. The logged temperatures are shown in Figure 3-1.

Tem

pera

ture

°C (3

0 s

mea

n)

1200

1000

800

600

400

200

0

Isophthalic unloaded Isophthalic loaded ASTM E119 Fire curve BS EN 1363-2 Hydrocarbon curve

Loaded grating failed 00:01:30

Unloaded grating failed 00:05:22

00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 Time from ignition (mm:ss)

Figure 3-1: Thermocouple logged temperatures for Isophthalic polyester grating tests (30 second average).

After the fire, both gratings were retrieved. The loaded grating split into two pieces that remained intact whilst the unloaded grating disintegrated on handling (Figure 3-2).

12

Figure 3-2: Unloaded Isophthalic polyester grating following exposure to a hydrocarbon pool fire.

3.1.2 Phenolic

The performance of the 60% open area phenolic gratings from both manufacturers was similar. The pre-loaded samples began to distort and allowed the metal box to slide off, into the pool between 2:47 and 5:11 minutes after ignition. Most of this variation can be explained by the position of the gratings. It took approximately 1 minute for the temperature of the downwind gratings to reach a steady value whilst it took twice as long for the upwind gratings.

In the case of each of the three loaded gratings, the sagging occurred towards the middle of the pool fire where the temperature was highest. After 17 minutes from ignition, one of the unloaded phenolic gratings from manufacturer A lost structural integrity. The cross braces failed, allowing the I-beams to separate and the grating fell into the fire tray.

The gratings were weighed before and after the fire and these data are shown in Table 3-1.

13

Table 3-1: Masses of 60% open area phenolic gratings

Sample numbers Manufacturer Initial mass (g) Final mass (g) Mass loss (g) 260612A260612B 040912D260612C*260612D#040712A040712B 040912C 040912E (Steel)

A A A A A B B B

5807 5889 5795 5832 5817 5892 5917 5897 14461

4456 4692 4443

5169 5587 5476 5281 14127

1351 (23%) 1197 (20%) 1352 (23%)

648 (11%) 305 (5%) 441 (7%) 616 (10%) 334 (2%)

* Grating fell apart during fire # Grating fell into water when it failed, protecting it from further exposure

Two heavier, 48% open area, phenolic gratings were exposed to a pool fire without loading. Both samples sagged during the test whilst the percentage mass loss was approximately the same as the lighter 60% open area grating and these data are provided in Table 3-2.

Table 3-2: Masses of 48% open area phenolic gratings

Sample numbers Initial mass (g) Final mass (g) Mass loss (g) 040912A 7790 5837 1953 (25%) 040912B 7816 5850 1966 (25%)

The thermocouple data for the phenolic gratings are provided in Figure 3-3.

14

700av

600°C (3

0 s

erag

e)

Manufacturer A 60% 260612A Manufacturer A 60% 260612B

Unloaded grating fails 16:58

Manufacturer A 60% 260612C

Tem

pera

ture

500 Loaded gratings fail 2:47 / 4:30 / 5:11

Manufacturer A 60% 260612D Manufacturer A 60% 040912D Manufacturer B 60% 040712A

400 Manufacturer B 60% 040712B Manufacturer B 60% 040912C Manufacturer A 48% 040912A

300 Manufacturer A 48% 040912B ASTM E-119 Fire curve

200 BS EN 1363-2 Hydrocarbon Steel

100

1200

1100

1000

900

800

0 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00

Time from ignition (mm:ss)

Figure 3-3: Thermocouple logged temperatures for phenolic grating tests (30 second average).

3.2 POST FIRE EVALUATION

3.2.1 Post Fire Visual Examination

Post fire visual examinations were reserved for phenolic and steel gratings only, given that the isophthalic polyester gratings did not survive the fire exposure. A select number of images for each grating can be found in Appendix C and only general observations are provided here. Perhaps the most notable observations post fire were the stark, discernable differences in appearance of the FRP gratings before and after exposure, coupled with the lack of structural integrity displayed by the FRP gratings compared to the steel grating.

To a varying extent, the FRP gratings appeared to be in an essentially “fragile” state with noticeable resin loss revealing glass fibres in places (Figure 3-4). The FRP gratings exhibited, to varying degrees, local movement of the bearing bars in the longitudinal direction suggesting that the ability of the cross rod system to resist such loads after a fire exposure is compromised. On closer inspection, it was found that a number of cracks were identifiable in the proximity of the cross rod/bearing bar interface (Figure 3-5).

15

Figure 3-4: Resin loss revealing fibrous reinforcement on bearing bars.

Furthermore, in the case of Manufacturer A’s gratings there were a number of prominent cracks in the bearing bars initiating from the tensile face (Figure 3-5). To varying extents the gratings appeared to have “sagged”, this being most prominent for the gratings that were loaded during the fire testing.

Figure 3-5: Evidence of cracks around the bearing bar/cross rod interface and bearing bar.

In contrast, no discernable lack of integrity was identified when handling the steel grating. As a result of the fire exposure the steel appeared to be coated in a voluminous surface layer, the identity of which was not determined as part of this study (Figure 3-6). This surface layer could be easily removed yielding a metallic grating comparable to that before exposure.

16

Figure 3-6: Steel grating post fire.

3.2.2 Post Fire Testing

Post-loaded tests were performed in accordance with PFM 2-98 and dynamic impact tests, as detailed in Section 2.3.2. A comprehensive overview of the specimens and results of this testing are provided in Appendix D. The results are summarised below.

3.2.2.1 Post-Loaded Testing in accordance with PFM 2-98

All of the FRP and steel gratings that were loaded with the 40 kg mass successfully passed with no gratings collapsing during the test. Further, all of the FRP gratings successfully exceeded the requirements of PFM-98 by remaining intact at a load per unit area greater than or equal to 4.5 kN/m2. The steel grating outperformed the FRP gratings and the testing was curtailed when a load of 20 kN/m2 was sustained without collapse. The data for this testing are provided in Table 3-3.

Table 3-3: UDL sustained by the FRP and steel grating without collapse.

Specimen Manufacturer A phenolic (60% open area) Manufacturer A phenolic (48% open area) Manufacturer B phenolic (60% open area) Steel grating

Load per unit area (kN/m2) 6.01 4.70 11.95 20+

3.2.2.2 Dynamic Testing

It was found that all FRP gratings were seriously damaged as a result of the dynamic loading test. In many cases the damage was limited, as expected, to the point at which the foot contacted the grating during forward travel. However, the overall effect of this damage was to seriously compromise the integrity of the grating as a whole. The steel grating displayed no discernible damage as a result of the dynamic testing (Figure 3-7).

17

Figure 3-7: FRP (left) and steel (right) gratings post dynamic testing

18

4. DISCUSSION

This study was initiated for two reasons. Firstly, FRP gratings are increasingly used on offshore oil and gas installations, and secondly, there were concerns that the ASTM E-119 cellulosic fire exposure specified in PFM 2-98 was not representative of the fires that could be realistically anticipated in an offshore environment. Thus, the aim of this piece of work was to evaluate the performance of FRP gratings during and after exposure to a hydrocarbon pool fire.

Given the preliminary nature of this work, the intention was not to perform an exhaustive array of tests, but rather to gain a broad appreciation of the performance of FRP gratings after such exposures, potentially leading to a more informed, structured and detailed programme of work in the future.

PFM 2-98 sets out fire test requirements in terms of structural fire integrity, fire retardance, flame spread and smoke generation. As part of this study, phenolic gratings with a Structural Fire Integrity Level 2 (L2) rating were sourced from two manufacturers and these were tested alongside isopthalic polyester gratings from one manufacturer and a steel grating approved for offshore service.

As expected, it was found that both the loaded and unloaded isopthalic polyester gratings failed after a short exposure time, 1.5 minutes and 5.5 minutes respectively. The three loaded phenolic gratings that were tested as part of the programme all shed the 40 kg load after a relatively short period of time. Manufacturer A’s 60% open area gratings failed after 2:47 minutes and 4:30 minutes, whilst manufacturer B’s grating shed the load after 5:11 minutes. Perhaps more concerning was the fact that one of Manufacturer A’s unloaded phenolic gratings failed after approximately 17 minutes. In all other cases, the unloaded phenolic gratings remained in-situ and this was also the case for the steel grating.

Mass measurements taken after the pool fire exposure indicated that all of the phenolic gratings had reduced in mass, and that this was, in general, more pronounced for Manufacturer A’s grating. Such observations are consistent with data presented in the literature for glass reinforced phenolic laminates (Gibson & Mouritz, 2006). Visual examinations highlighted bare fibrous reinforcement, cracking and reduced structural integrity. The FRP gratings appeared “fragile” in comparison to the steel grating which displayed no cracking or gross deformation after the fire exposure.

All of the phenolic gratings successfully met the post-loaded test criteria used for structural fire integrity Level 2 certification within PFM 2-98. However, it is notable that the testing criteria to achieve Level 2 relies on load tests where the load application is quasistatic, ultimately resulting in a static load.

A dynamic test only forms part of the qualifying requirements within PFM 2-98 if the L1 rating is sought. Importantly therefore, the implication is that either the L2 gratings fail to satisfy the performance requirements to achieve a L1 rating, or testing has not taken place to establish their performance in this regard. At the time of writing it is unknown which assertion is correct. Nevertheless, the dynamic testing performed as part of this programme has demonstrated that a 90 kg male running over certified L2 FRP gratings (that have been subjected to a ~15-17 minute hydrocarbon pool fire) results in failure. In all cases the L2 FRP gratings failed immediately upon the foot striking the grating. The steel grating did not exhibit such behaviour.

19

5. CONCLUSIONS

The conclusions detailed below are based on the results attained as part of this programme. They have been derived from evaluating the performance of FRP gratings exposed to hydrocarbon pool fires in general accordance with the methodologies detailed within PFM 2-98.

1. As part of its qualification requirements for structural fire integrity gratings, the US Coast Guard specifies that sample gratings are tested in a furnace and exposed to a standardised time-temperature curve for a cellulosic fire (ASTM E-119). The exposure time is 60 minutes rising to a final temperature of 927 °C. The temperature data obtained as part of this study demonstrate that this time-temperature profile is not representative of a hydrocarbon pool fire scenario, which can reach this temperature in 5 minutes. Therefore the results may be misinterpreted to give a false sense of confidence that the gratings can support loads for longer than they can in an actual hydrocarbon pool fire.

2. When exposed to a hydrocarbon pool fire, loaded and unloaded isopthalic polyester gratings fail after 1.5 minutes and 5.5 minutes respectively.

3. When exposed to a hydrocarbon pool fire, loaded glass reinforced phenolic gratings (qualified as structural fire integrity level 2) deform, thereby shedding their load within 6 minutes.

4. When exposed to a hydrocarbon pool fire of approximately 15-17 minutes duration, the structural integrity of loaded and unloaded reinforced phenolic gratings (qualified as structural fire integrity L2) appears to be compromised. Despite this, all of the surviving gratings met the post-loaded test criteria for qualification as L2 according to PFM 2-98.

5. When exposed to a hydrocarbon pool fire of approximately 15-17 minutes duration, glass reinforced phenolic gratings (qualified as structural fire integrity L2) failed when subjected to the dynamic loads applied as a consequence of a 90 kg male running over them despite passing the post-loaded test criteria for qualification as L2 according to PFM 2-98.

6. Further work is necessary to understand fully the behaviour of composite gratings in a fire and develop a rigorous and robust test procedure for ensuring they are fit for installation offshore.

20

6. REFERENCES

1. US Department of Transportation. (1998). United States Coast Guard. Policy File Memorandum on the Use of Fiber Reinforced Plastic (FRP) Gratings and Cable Trays. PFM 2-98.

2. Gibson, A.G., Mouritz, A. P. (2006). Fire Properties of Polymer Composite Materials.

21

22

APPENDIX A

Excerpt from PFM 2-98:

7.

23

24

25

APPENDIX B

Test Specimen Dimensions

Length (mm)

Width A (mm)

Width B (mm)

Manufacturer A Glass reinforced phenolic (60% open area) Manufacturer B Glass reinforced phenolic (60% open area) Manufacturer A Glass reinforced isophthalic polyester (60% open area) Manufacturer A Glass reinforced phenolic (48% open area) Steel

1200

1200

1200

1200

1200

280 300

280 300

280 300

310 320

Width = 294 mm

26

APPENDIX C

C1 TEST 1

C1.1 Results - Fire Testing

Samples Source Material Open Area Load (kg) Sample No. A B C D

Manufacturer A Manufacturer A Manufacturer A Manufacturer A

Phenolic PhenolicPhenolicPhenolic

60% 60% 60%

60%

40

40

260612A 260612B 260612C 260612D

A B C D

Tem

pera

ture

°C (3

0 s

aver

age)

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00


Manufacturer A 60% 260612A Manufacturer A 60% 260612B Manufacturer A 60% 260612C Manufacturer A 60% 260612D ASTM E119 Fire Curve BS EN 1363-2 Hydrocarbon

Unloaded grating fails 16:58

27

Source A A A A Material Phenolic Phenolic Phenolic Phenolic Loading 40 kg 40 kg Sample no 260612A 260612B 260612C 260612D Time from ignition Temp. (°C) Temp. (°C) Temp. (°C) Temp. (°C) 00:00 12.69 16.45 15.83 23.85 00:30 152.56 582.33 663.88 480.81 01:00 397.61 892.21 871.47 600.07 01:30 439.04 953.18 947.87 626.17 02:00 579.90 986.95 995.32 662.03 02:30 683.47 956.15 965.90 709.76 03:00 702.76 919.76 920.37 778.11 03:30 692.16 955.80 986.46 04:00 713.72 904.02 1000.03 04:30 752.68 912.90 988.36 05:00 926.50 987.66 05:30 931.70 986.26 06:00 935.04 1004.62 06:30 970.69 991.17 07:00 965.28 1002.92 07:30 969.75 990.68 08:00 936.41 1007.45 08:30 920.24 940.24 09:00 911.85 936.30 09:30 903.58 909.54 10:00 935.36 965.99 10:30 831.68 932.08 11:00 948.59 1007.61 11:30 952.68 991.41 12:00 895.81 965.78 12:30 953.24 978.57 13:00 1001.08 970.77 13:30 984.23 931.99 14:00 935.89 932.97 14:30 954.38 983.23 15:00 917.98 928.02 15:30 915.83 906.96 16:00 872.48 912.15 16:30 892.29 905.13 17:00 925.09

28

29

C1.2 Results - Post Fire Visual Examination

SAMPLE NO: 260612A

30

SAMPLE NO: 260612B

31

SAMPLE NO: 260612C

32

SAMPLE NO: 260612D

33

C2 TEST 2


Samples Source Material Open Area Load (kg) Sample No. A B C D

Manufacturer B Manufacturer B Manufacturer A

Manufacturer A

Phenolic PhenolicIsophthalic polyester Isophthalic polyester

60% 60%

60% 60%

40

40

040712A 040712B 040712C 040712D

A B C D

Tem

pera

ture

°C (3

0 s

aver

age)

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

Phenolic Manufacturer B 60% 040712A

Phenolic Manufacturer B 60% 040712B

Isophthalic Manufacturer A 60% 040712C

Isophthalic Manufacturer A 60% 040712D

ASTM E119 Fire curve

BS EN 1363-2 Hydrocarbon

00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00


34

Source B B A A Material Phenolic Phenolic Isophthalic Isophthalic Loading 40 kg 40 kg Sample no 040712A 040712B 040712C 040712D Time from ignition Temp. (°C) Temp. (°C) celsius celsius 00:00 14.59 18.92 18.92 17.68 00:30 126.37 468.00 714.21 447.03 01:00 344.48 608.44 721.96 592.03 01:30 417.91 778.88 783.20 363.16 02:00 574.80 817.16 831.40 42.43 02:30 670.22 880.34 889.65 26.06 03:00 687.13 890.96 911.62 20.95 03:30 661.54 935.46 934.03 19.82 04:00 737.61 920.61 932.28 17.98 04:30 755.60 910.08 920.35 17.15 05:00 783.29 924.22 879.59 16.86 05:30 728.64 878.26 235.18 19.44 06:00 876.71 21.19 20.13 06:30 833.16 20.37 20.23 07:00 882.97 18.97 18.64 07:30 875.40 19.24 18.82 08:00 888.94 18.93 17.15 08:30 909.72 18.73 16.76 09:00 874.99 18.13 16.40 09:30 886.03 18.45 15.80 10:00 896.09 17.69 15.19 10:30 840.79 11:00 837.77 11:30 888.53 12:00 899.97 12:30 909.20 13:00 897.38 13:30 893.04 14:00 851.42 14:30 817.00 15:00 828.64 15:30 772.72 16:00 625.18 16:30 496.99 17:00 424.39

35

36

C2.2 Results – Post Fire Visual Examination

SAMPLE NO: 040712A

37

SAMPLE NO: 040712B

38

SAMPLE NO: 040712C

39

SAMPLE NO: 040712D

40

C3 TEST 3


Samples Source Material Open Area Load (kg) Sample No. A Manufacturer A Phenolic 48% - 040912A B Manufacturer A Phenolic 48% - 040912B C Manufacturer B Phenolic 60% - 040912C D Manufacturer A Phenolic 60% - 040912D E Manufacturer C Steel - 040912E

A B C D E

Tem

pera

ture

°C (3

0 s

aver

age)

1200

1100

1000

900

800

700

600

500 Manufacturer A 48% 040912A Manufacturer A 48% 040912B Manufacturer B 60% 040912C

400 Manufacturer A 60% 040912D Steel 040912E

300 ASTM E119 Fire curve BS EN 1363-2 Hydrocarbon

200

100

0 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00


41

Source A A B A C Material Phenolic Phenolic Phenolic Phenolic Steel Loading Sample no 040912A 040912B 040912C 040912D 040912E Time from ignition Temp. (°C)Temp. (°C) Temp. (°C) Temp. (°C) Temp. (°C) 00:00 10.12 10.75 10.89 17.16 39.95 00:30 44.66 95.18 122.08 96.82 325.61 01:00 469.69 672.67 712.20 692.99 735.27 01:30 734.67 845.21 804.54 893.22 778.23 02:00 864.23 884.16 857.74 950.95 782.77 02:30 921.75 931.81 865.94 907.71 828.18 03:00 930.36 947.61 898.66 923.74 862.13 03:30 964.35 978.70 921.00 932.26 859.50 04:00 960.17 982.64 867.39 855.73 814.41 04:30 981.34 999.26 931.52 944.16 926.52 05:00 974.85 1008.20 943.24 987.44 1019.50 05:30 963.55 994.34 942.27 987.50 958.99 06:00 967.12 975.24 920.20 963.40 895.12 06:30 948.17 958.89 929.11 943.63 861.83 07:00 953.48 977.68 937.16 926.31 907.01 07:30 919.23 952.31 930.64 945.41 881.37 08:00 941.85 977.49 879.81 864.59 768.46 08:30 955.78 975.29 946.36 937.52 892.25 09:00 924.77 985.88 928.47 909.56 836.86 09:30 880.35 972.06 944.63 933.80 854.25 10:00 884.96 957.66 952.39 956.32 879.01 10:30 898.41 979.82 941.74 957.81 888.71 11:00 938.22 977.86 923.63 933.15 815.52 11:30 884.87 973.05 898.82 869.41 795.79 12:00 888.44 947.69 916.49 875.22 839.04 12:30 900.79 973.26 915.05 902.56 825.76 13:00 943.81 953.90 935.97 896.09 867.11 13:30 901.12 932.32 877.31 850.35 878.45 14:00 824.84 894.86 884.24 826.31 768.27 14:30 844.36 909.08 876.13 841.42 805.34 15:00 737.50 835.21 841.25 760.78 708.40 15:30 614.29 749.19 768.74 630.21 673.28 16:00 375.68 491.31 650.39 467.59 567.91 16:30 280.78 369.27 519.94 361.38 495.85 17:00 209.71 297.94 454.80 292.29 448.02

42

43

C3.1 Results – Post Fire Visual Examination

SAMPLE No: 040912A

44

SAMPLE NO: 040912B

45

SAMPLE NO: 040912C

46

SAMPLE NO: 040912D

47

SAMPLE NO: 040912E

48

Sample No. 260612B 040912B 040712B

040912E

260612B 040912B 040712B

APPENDIX D Note 1: As only one steel grating was used for testing, this was subsequently used for all D1 POST-LOADED TESTING post-loaded tests (as per PFM 2-98) and

49

USCG PFM 2‐98 LEVEL 3 POST‐LOADED TEST

Result Pass Pass Pass

Pass

USCG PFM 2‐98 LEVEL 2 POST‐LOADED TEST

Sample No.

040912E

19.20 18.45 18.95 18.75 19.25 18.75 18.90 18.90 19.15 18.85 19.15 18.45

19.15 18.90 19.25 18.85 19.10 18.40 19.10 18.55 18.90 18.50 19.15 18.40 19.05 18.45 19.10 18.35 18.85 18.35 18.85 18.45 18.75 18.70 19.05 18.70 18.95 Collapse 18.75 18.40 Collapse 19.05 18.35

19.15 18.50 18.75 18.70 18.75 18.65 18.65 18.45 18.65 18.70 18.75 18.55 19.05 18.45 18.80 18.80 Collapse 18.65

18.70 18.85 18.60 18.75 18.85 19.15 19.25 19.25 19.25 18.90 19.00 19.10

Mass of

individu

al blocks ap

plied to

grating

(kg)

Test discontinued

Supported Load (kg) 171.40 148.65 341.05 599.25

Total area (m2) 0.28 0.31 0.28 0.29

Load per unit area (kN/m2) 6.01 4.70 11.95 20.00

dynamic testing.

Note 2: Mass of mat used in post-loaded tests as per PFM 2-98 is not included.

Note 3: All data presented to 2 dec. places.

SAMPLE NO: 260612B

50

SAMPLE NO: 040912B

51

SAMPLE NO: 040712B

52

SAMPLE NO: 040912E

53

D2 DYNAMIC TESTING

SAMPLE NO: 040912D

SAMPLE N: 040912C

54

SAMPLE NO: 040912A

SAMPLE NO: 040912E

55

56

57

Published by the Health and Safety Executive 10/12





This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

RR950

www.hse.gov.uk

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