Report on a crude oil pool fire, Arnhem, Netherlands

Report on a crude oil pool fire, Arnhem, Netherlands.

TS13120-R01-ISSUE 1 Fire investigation report

for:

Kingspan Ltd GreenField Business Park No 2

Greenfield Holywell

Flintshire CH8 7HU

Report on a crude oil pool fire, Arnhem, Netherlands | TS13120-R01-Issue 1

TENOS | issued: 21 June 2013 Page 2 of 16

Issue and amendment record

Issue Date Author Checked by Amendment details

D1 27 March 2013 J Barnfield R Clinton Draft for review

I1 21 June 2013 J Barnfield A Hay First issue

Important information Except when specifically agreed in writing Tenos shall not be liable for any reliance placed on this report by any person other than the client named on the front page of this report. This report may only be forwarded to a third party if reproduced in full and without amendment to the content or presentation.



Contents: 1 Introduction 4

2 Brief description of facility 5

3 The fire 6

4 Conclusions 12

5 References 13

Annexes: A.1 Annex 1 – Estimation of radiant heat flux 14



1 Introduction 1.1 On the 18th January 2013 a fire involving crude oil occurred in an external equipment testing

area of a facility located in Arnhem, Netherlands that is used for the testing of equipment for the oil industry.

1.2 The test site was located adjacent to the main test building which was clad with Kingspan IPN,

polyisocyanurate insulated panels (Kingspan KS1000 AWP 60mm). 1.3 Kingspan Ltd instructed Tenos to examine the site of the fire and other available information to

evaluate the fire behaviour of the IPN panels used to clad the building. 1.4 John Barnfield of Tenos Ltd visited the site on 6 February 2013 and met with Joost Ebus of

Gelderland-Midden Brandweer (Fire service) who provided much helpful information about the fire.

1.5 On the date of the site visit much of the damaged test equipment had been removed and

temporary weather protection had been installed over the walls which prevented direct examination of the cladding panels. Therefore, this report is largely based upon information provided by the fire service, the operators of the test facility, Kingspan and public domain information from the internet.



2 Brief description of facility 2.1 The fire started in the external equipment test facility at a distance of approximately 15m from

the facade of the adjacent test building. The external facility covered an area of approximately 25m wide by 49m long and incorporated various pieces of oil processing equipment including two crude oil storage tanks.

2.2 The general arrangement of the test facility is illustrated below in figure 1.

Figure 1. General arrangement of external test facility

2.3 The external wall of the adjacent building was clad with Kingspan IPN panels (KS1000 AWP

60mm). At the top of the wall polyurethane (PUR) panels from an unknown source were used to form the parapet wall and these appeared to have suffered more damage by charring damage than the IPN panels.



3 The fire 3.1 The fire started at approximately 17.00hrs on 18th January 2013 and is thought to have occurred

as a result of the rupture of a heat exchanger which allowed the release of a mixture of hot crude oil and natural gas under at an initial pressure of 43 bar. The gas and oil mixture then ignited generating a fire plume that rose to approximately 30 metres high as illustrated in the photograph below.

Figure 1. Fire plume shortly after ignition 3.2 The first call to the fire service was received at 17:02:53 and their arrival at the scene was just

over 7 minutes later at 17:10:15. 3.3 Based upon video footage, largely taken from YouTube, it appears that the fire burned at a peak

intensity for approximately 10 minutes before the flames began to reduce significantly in height. 3.4 A representative of the facility’s operator indicated that a total of 20m3 of crude oil was

contained within the storage tanks and that approximately 5m3 was involved in the fire. 3.5 The following timeline of the progress of the fire has been derived largely from amateur video

footage available on YouTube and may not be completely accurate as the actual time at which individuals started their recording cannot be accurately assessed.



Table 1. Timeline derived from video observations of fire (all times are approximate)

Time (CET) Time from ignition (m:s)

Observations

17:02:00pm 0:00 Rupture of equipment releasing crude oil and natural gas mixture quickly followed by ignition. Flames rising to a height of approximately 30m

17:02:53 1:00 First call received by fire service 17:07:00 5:00 Flames 20m high with production of large quantities of black

smoke 17:08:00 6:00 Flames reducing to 10m high 17:09:30 7:30 Flames generally less than 10m high 17:09:45 7:45 Flaming on or adjacent to the surface of the building cladding

and self-sustaining flaming becomes visible at the roof/wall junction

17:10:15 8:15 Flaming on or adjacent to building wall dies down 17:11:00 9:00 Sustained flaming of roofing materials can be observed to

continue at the edge of the roof. 17:14:00 12:00 Flames dying down to 3 to 5 m in height 17:17:00 15:00 Burning now reduced to localised pool fires with flames of 1.5 to

2m high 17:19:00 17:00 Only relatively small isolated pool fires remaining 17:20:00 18:00 End of video information.

Commentary

3.6 During the initial stages of the fire the fire plume reached a height of approximately 30m which reduced to about 10m after 7 minutes of burning. There were anecdotal reports of the pool fire spreading to the building façade which would have caused direct flame impingement on the cladding. However, this was thought to be short lived and could not be confirmed from the available video evidence.

3.7 After approximately 7min 45s there appeared to be some surface flaming on the cladding. It is

assumed this was the burning off of the weather protective coating on the panels either as a result of the high levels of heat radiation or the direct flame impingement mentioned above.

3.8 After about 30s the flaming on the wall surface died away and there was no sustained burning

on the façade. However, at about 9 minutes there was evidence of sustained burning at the junction between the built up roof and the parapet of the external wall (see figure 8).

3.9 The extent of damage to the edge of the roof can be seen in figure 2. Ignition in this area is

likely to have occurred as a result of a combination of the high levels of heat radiation received and the pilot flame provided by the short lived flaming across the external panels.

3.10 The extent of surface damage to the wall panels is shown in figure 3. Figures 4, 5 & 6 show the

extent of charring of the IPN core. 3.11 Figure 8 illustrates that burning at the interface between the PUR parapet and built-up roofing

system after the main fire had been extinguished.



Figure 2. Damage to roof construction at junction with external wall

Figure 3. External blackening & distortion of panels (premises logo obscured)



Figure 4. Section of IPN panel after removal from wall

Figure 5. IPN panels after removal from building 3.12 The heat radiation caused surface rippling and delamination of of the steel facing of the

cladding panels and some charring of the IPN core but there is no evidence to suggest that the core material suffered substantial degradation or assisted in propagating flame spread or charring through the core.



Figure 6. View of joint after removal of adjacent panel 3.13 Inside the building there was evidence of high level smoke staining and brownish material

dripping down the interior wall surface (see figure 7).

Figure 7. Internal smoke staining and dripping on internal face of wall



Figure 8. Sustained flaming at parapet-roof interface after fire generally extinguished 3.14 It is not clear whether the smoke staining was due to the ingress of smoke from the fire or

pyrolysis of one or more of the wall construction materials. The dark drips of material are thought to be from the melting of adhesive products used at the intersection between the IPN wall panels and the PUR cored parapet wall.

3.15 The wall construction does not appear to have been subject to any sustained periods of direct

flame impingement but during the initial peak period of fire intensity (10 minutes) it would have been subject high levels of heat radiation. The ignition of the roof edge indicates that incident radiation levels were well in excess of the intensity at which pilot ignition may be expected to occur (i.e. 12.6KW/m2).

3.16 An estimate of the likely intensity of the heat radiation received by the wall has been made (see

annex 1) and indicates an incident radiation intensity of approximately 24kW/m2. 3.17 This value of 24kW/m2 is roughly double the allowable value of 12.6kW/m2 used in guidance to

UK Building Regulations5.1. At this intensity of radiation the ignition of the roof covering materials at the wall junction (after approximately 8 minutes) is not surprising.

3.18 At this intensity of heat radiation the steel facings of the cladding panels exhibited distortion and

delamination but the IPN core material only appears to have suffered surface charring. There was no evidence to suggest that the panel core promoted the spread of fire or charred to any significant depth.



4 Conclusions 4.1 Based upon a site visit, video information from YouTube, and additional photographs and

information kindly provided by the Arnhem Fire Service the following conclusions can be drawn. 4.2 The fire started at about 5.00pm and continued to burn intensely for about 10 minutes. During

this period the flame plume was initially 30m high and reduced to about 10m high. After this initial period the fire died down significantly to form a number of smaller separate pool fires. The available video information ends after about 18 minutes of burning; at which time only small pools of flaming remained.

4.3 There appears to have been little sustained direct flame impingement on the external cladding

of the building. However, the cladding would have been subject to very high levels of radiant heat flux from the fire plume and this has been estimated to be of the order of 24kW/m2. This is approximately double the 12.6kW/m2 that is normally used as a basis for design under UK Building Regulations5.1.

4.4 Ignition and sustained flaming at the junction of the roof with the PUR parapet panels occurred

after approximately 8 minutes and this is consistent with the radiant heat flux on the roof and wall significantly exceeding 12.6kW/m2.

4.5 At the intensity of radiation received, some surface flaming of the cladding panels occurred but

this ceased after approximately 30s (presumably after the surface coating had burned away). There was otherwise no evidence of self-sustaining flaming from the IPN panel surface or at joints between panels.

4.6 As a result of the intensity of heat radiation, the steel facings of the panels became rippled and

delaminated from the IPN foam core but there was only limited foam degradation at the core surface.

4.7 Despite the intensity of heat radiation being sufficient to cause ignition and sustained burning at

the junction between the roof and PUR parapet panels there was no evidence of any significant charring of the IPN panel cores or the promotion of fire spread via the IPN core.



5 References 5.1 External fire spread, Building separation and boundary distances, Report BR 187. BRE 1991 5.2 NISTIR 6546. Thermal Radiation from large Pool Fires. National Institute of Standards and

Technology. November 2000.



A.1 Annex 1 – Estimation of radiant heat flux A.1.1 The following calculations provide a rough estimate of the intensity of the radiant heat flux that

may have been received by the wall of the adjacent building. A.1.2 Based on video data and examination of the damage to surrounding equipment the fire plume

appears to have a diameter of approximately 10m2. A.1.3 For design purposes it is usual to assume that for hydrocarbon pool fires the fire plume will have

an emissive power of 100kW/m2. However, this generally provides an overestimate as the emissive power of the flame tends to reduce with increasing pool diameter. Data from the US National Institute of Standards and Technology5.2 indicates that the emissive power of a 10m diameter hydrocarbon (gasoline) pool fire is likely to be of the order of 60kW/m2.

A.1.4 Assuming an average flame diameter of 10m and a height of 20m (estimated from video

evidence) the level of heat radiation on the building façade can be estimated. A.1.5 The centre of the pool was located approximately 14m from the building façade and assuming a

10m flame diameter the separation between the building and the plume envelope would have been approximately 9m.

A.1.6 For calculation purposes the flame has been assumed to be square on plan with the following

dimensions: Width of flame front 10m Height of flame 20m Distance of flame front from building façade 9m A.1.7 To calculate the level of radiation incident on the building façade the configuration factor (Φ) has

been calculated using proprietary software as follows:

CONFIGURATION FACTORS - (assuming vertical radiator) +ve angles in ZY ------------------------------------------- ¦ |Z2 ¦ <------ ¦ Quadrant 1 | Quadrant 2 ¦ +ve angles ¦ | ¦ in ¦X2 _ _ _ _ _ _ _ _ _ = _ _ _ _ _ _ _ _ _ X1¦ -ve XY or theta ¦ = ¦ ¦ Quadrant 3 | Quadrant 4 ¦ ¦ | ¦ ¦ |Z1 ¦ ------------------------------------------- -ve angles in ZY. Receiver located perpendicular to intersection of Q1,Q2,Q3 & Q4. Receiver located perpendicular to intersection of Q1,Q2,Q3 & Q4. WIDTH OF QUADRANT No1 5m WIDTH OF QUADRANT No2 5m HEIGHT OF QUADRANT No1 10m HEIGHT OF QUADRANT NO3 10m SEPARATION DISTANCE 9m RADIATOR AND RECEIVER ARE PARALLEL CALCULATED CONFIGURATION FACTOR = 0.40669



A.1.8 The incident radiation flux can then be derived from the following equation: Ir(receiver) = Φ Ie(emitter) kW/m2 Ir = 0.4067 x 60kw/m2 = 24.4 kW/m2 A.1.9 This provides an estimate of the intensity of heat radiation that would have been received at

high level on the wall and is approximately double the 12.6kW/m2 at which the pilot ignition of dry wood would be expected to occur.



Documents

Report on a crude oil pool fire, Arnhem, Netherlands