A review of the applicability of the jet fire resistance test of passive fire protection materials to a range of release scenarios

https://doi.org/10.1016/j.psep.2018.12.004Get rights and content

Abstract

In 2017 the UK Health and Safety Executive commissioned a report (MH/17/27) on the suitability of the ISO 22899-1:2007 jet fire resistance test (JFRT) as a means of demonstrating performance of Passive Fire Protection (PFP) materials or systems to a range of jet fire scenarios. The aim was to address current industry concerns regarding the suitability of the test for characterising PFP materials response in’ high heat flux’ scenarios.

The characterisation of a jet fire in terms of a single heat flux value is found to be an inadequate means of specifying the severity of the hazard. Instead, a detailed description of the nature of the release should be provided. To this end the flame characteristics are compared that influence PFP materials response for a range of release scenarios, including gas, flashing liquids, crude-oil, gas-liquid mixes (two-phase), hydrogen, cryogenic releases and releases into confined areas.

The applicability of the JFRT to the various release scenarios is assessed through comparison of the conditions within the scenarios to those within the large-scale natural gas release scenario used during validation of the JFRT.

Introduction

Jet fires are recognised as severe hazard scenarios that require a test method capable of simulating both the high thermal and mechanical loads placed on passive fire protection (PFP) materials during direct jet-fire impingement. Following the Piper Alpha disaster and recommendations from the public enquiry (Cullen, 1990), a working group with members from the U.K., Norway and the U.S.A. developed an interim jet fire test method (HSE, 1993) (HSE, 1995), which then formed the basis of the international standard ISO 22899-1: 2007 (International Standardisation Organisation, ISO 22899-1, 2007). The ISO jet fire resistance test (JFRT) is currently the most widespread test method used to demonstrate PFP material resilience in jet-fire scenarios.

Recent years have seen an increase in concerns being raised by parties across industry that the current ISO jet fire resistance test (JFRT) is not representative of more severe jet fire scenarios. Such concerns have almost entirely been related to the heat flux values the specimen is exposed to during a test (Fire and Blast Information Group, 2018). Alternative methods of test, often referred to as “high heat flux tests”, have been developed by individual test laboratories, and are being increasingly requested by PFP manufacturers, engineers and operators. Such alternative methods of test are unpublished and without validation studies.

The growth of ad-hoc test methods is generating confusion within industry, leading some to call into question whether the JFRT is applicable to any jet fire scenario. There is a clear desire within industry for clarity on the applicability of the current JFRT and, if the test is not applicable to a given scenario, clarity on how a PFP system can then be tested to demonstrate resilience.

In early 2017 the U.K. Health and Safety Executive commissioned a literature review of large-scale jet fire tests (Health and Safety Executive, 2017) to address the situation. The primary aims were to assess the applicability of the JFRT to a range of jet-fire release scenarios, discuss whether further test method development is justified, and propose a plan for test development if deemed necessary. The literature review will be published as report MH/17/27 (hereafter referred to as the report).

Section snippets

Jet fire characterisation

The nature of jet fires has been studied in some detail (Lowesmith and Hankinson, 2007) (FABIG, 2014) (Chamberlain, 2002). Unlike furnace-based tests, jet fires produce highly non-uniform conditions and PFP system failure is far more likely to be localised, sudden and complete. Predicting the response of a PFP material in a jet fire is not trivial. The severity of a jet fire comes from a combination of thermal and mechanical loads when it impinges on an object, and the peak values of each are

Validation of the JFRT

Having stated the importance of characterising a jet fire through an appropriate description of the release and environment, and the importance of assessing the severity in terms of the thermal and mechanical loads applied, attention must be given to the large-scale releases characterised around the time of the JFRT development in the early 1990s. Although the quantity of large-scale jet fire test evidence was limited compared with that available today, the working group had access to detailed

Methodology

To the knowledge of the authors, there have been no tests performed that seek to characterise PFP material response in large-scale jet fires other than the 3 kg/s natural gas validation studies described above and a study of PFP performance on LPG tanks (HSL, 1996). In the absence of direct test evidence, an assessment of the applicability of the JFRT to alternative scenarios can be performed through consideration of the test aspects that affect PFP material response, and comparison of the

Conclusions

In this article the applicability of the JFRT to alternative release scenarios has been assessed by comparison of the conditions within the alternative scenarios to those within the 3 kg/s sonic natural gas release (referred to herein as the benchmark test).

This benchmark test, and by extension the JFRT, is concluded to be representative of unconfined and partially confined flashing liquid releases, or gaseous releases of similar flow rates and reservoir pressures (60 bar).

It is concluded that

Disclaimer

The paper's contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

References (33)

  • Acton et al.

    The Applicability of the Jet Fire Resistance Test

    (1998)
  • Al-Hassan et al.

    Jet fire resistance for passive fire protection materials on tubular sections

    Proceedings of the 7th International Offshore and Polar Engineering Conference

    (1997)
  • A. Beard et al.

    The Handbook of Tunnel Fire Safety

    (2005)
  • BG Technology

    Large SCale Experiments to Study Jet Fires of Crude Oil/Gas/Water Mixtures

    (2000)
  • British Gas R&T

    GRC R0367, Large Scale Experiments to Study Horizontal Jet Fires of Mixtures of Gas and Butane

    (1995)
  • British Gas R&T

    GRC R0659, Large Scale Natural Gas Jet Fires Impacting on Flat Surfaces

    (1996)
  • British Gas R&T

    GRTC R1019, Blast and Fire Engineering Project Phase 2 - Horizontal Jet Fires of Oil and Gas

    (1997)
  • G. Chamberlain

    An Experimental Study of Large-Scale Compartment Fires

    (1994)
  • Chamberlain

    Controlling hydrocarbon fires in offshore structures

    Proceedings of the Annual Offshore Technology Conference

    (2002)
  • Cowley and Tam, Consequences of pressurised LPG releases: the Isle of Grain full scale experiments, in Gastech 88,...
  • T.H.L. Cullen

    The Public Inquiry into the Piper Alpha Disaster

    (1990)
  • FABIG

    Technical Note 13, Design Guidance for Hydrocarbon Fires

    (2014)
  • Fire and Blast Information Group, Technical Newsletter Issue...
  • Hankinson et al.

    Jet Fires Involving Releases of Crude Oil, Gas and Water, Process Safety and Environmental Protection

    (2007)
  • Health and Safety Executive

    A Review of the Applicability of the Jet Fire Resistance Test of Passive Fire Protection Materials to Severe Release Scenarios MH/17/27

    (2017)
  • HSE, OTO 93028,...
  • Cited by (16)

    • An experimental study of jet fires in pits

      2022, Process Safety and Environmental Protection
      Citation Excerpt :

      Many studies have been conducted on the combustion behavior of jet fires. Free jet fires in still air received much attention (Kalghatgi, 1984), and then the research expanded to jet flames under cross wind (Wang et al., 2017) and jet flows underwater (Zhang et al., 2020), in the atmosphere of different pressures (Rengel et al., 2020; Wang at al., 2019), in a rotating flow field (Zhou et al., 2019), or the impinging interaction between jet fire and barrier wall (Bradley et al., 2019; Wang et al., 2021) or water mist spray(Liu et al., 2022). The geometrical and thermal properties of the flame are the major focal points of abovementioned studies.

    • Jet fires involving releases of gas and solid particle

      2021, Process Safety and Environmental Protection
      Citation Excerpt :

      In comparison, the sand and soil were observed to enter the high-pressure hydrogen jet fires in a field test, and the intensity of thermal radiation was found to increase (Acton et al., 2010), but the correlation is still unclear between solid particle entrainment and thermal radiation enhancement. In addition, the jet fire resistance test of passive fire protection materials only involves the release scenarios of gas, flashing liquid, crude-oil and gas-liquid mixture (Bradley et al., 2019). In short, the gas-solid jet fire seems to lack of consideration in terms of the thermal hazards and the reliability of protection barrier in process industry.

    View all citing articles on Scopus
    View full text