Yet again I am bringing this one back to the top of the list.<\/p>\n
SuDs and fire risks<\/strong><\/span>\u00a0 In a technical context, particularly in the UK, SuDs can be an acronym for Sustainable Drainage Systems which are methods to manage surface water runoff to mimic natural drainage.<\/p>\n My question: Is it possible that the use of plastic crates for SuDs installations has introduced a surprising and unanticipated fire risk?<\/strong><\/span><\/p>\n After ‘firewater’ I have added some historical information on three major UK fire disasters and comments on the counter-intuitive nature of the problem<\/span><\/strong>.<\/p>\n The Northern Ireland Environment Agency working with the Scottish Environment Protection Agency – have published a document on Guidance for Pollution Prevention<\/strong> that refers to Suds (in section 4.5) that can be found in the document here\u00a0<\/span><\/a><\/strong><\/p>\n There is also the CIRIA\u00a0 SuDs Manual C753 (968 pages) available if you are really interested in SuDs but this does not refer to fire risk.<\/p>\n The use of the term ‘firewater’\u00a0<\/span><\/strong>is particularly interesting.<\/span><\/span><\/p>\n When not used to refer to alcoholic spirits like whiskey or moonshine, “firewater” primarily refers to two things: polluted water from firefighting operations and, less commonly, water used for wildfire suppression<\/strong><\/span>.\u00a0<\/span>The term “firewater” can also refer to a type of whisky-based liquor, but when not a drink, it is associated with the runoff of water from a fire, which can contain toxic contaminants and requires careful handling and disposal.\u00a0<\/span><\/span><\/span><\/strong><\/span><\/p>\n NEW<\/span> Historical Fire Incidents and Material Risks<\/strong><\/p>\n Three major UK fire disasters illustrate the critical importance of understanding how building materials behave under fire conditions: the Bradford City stadium fire (1985), the King’s Cross Underground fire (1987), and the Grenfell Tower fire (2017). While these incidents occurred in very different settings, they share common factors:<\/strong><\/span> the rapid fire spread was accelerated by combustible materials that were not originally considered high-risk – Bradford’s wooden stands and accumulated debris, King’s Cross’s wooden escalators and paint layers, and Grenfell’s external cladding system. In each case, materials that seemed appropriately specified for their primary function created unexpected fire hazards that had not been adequately assessed.<\/strong><\/span><\/p>\n NEW\u00a0 <\/span>The Counter-Intuitive Nature of SuDS Fire Risk<\/strong><\/p>\n The concept of fire risk in water management systems appears paradoxical blind spot.\u00a0 These installations are designed to handle water, the primary firefighting medium. However, this counter-intuitive nature may be precisely why the fire risks associated with plastic SuDS components have received limited attention. Underground plastic crate systems, while effectively managing stormwater during normal operations, could potentially compromise both structural integrity and environmental safety during fire incidents – also then creating a “firewater” contamination pathway.<\/p>\n \u00a0 \u00a0My original post starts here:<\/span><\/span><\/strong><\/p>\n Is it possible that the use of plastic crates for SuDs installations has introduced a surprising and unanticipated fire risk? (link to previous post)<\/a><\/span><\/strong><\/p>\n Emerging Fire Risks Associated with the use of Plastic Crates to create underground Storm water Detention Systems: An Assessment of Current Knowledge Gaps and Safety Implications.<\/span><\/strong><\/p>\n ## Abstract – Ewan Larcombe with the assistance of Claude (Ai)<\/p>\n The increasing adoption of plastic modular crate systems for underground storm water detention presents potential fire safety risks that have received insufficient attention in current design standards and emergency response protocols. This paper examines the fire behaviour characteristics of thermoplastic materials, documented challenges in suppressing underground plastic fires, and identifies critical knowledge gaps in the assessment and mitigation of fire risks associated with large-scale plastic infrastructure installations beneath car parks and roadways.<\/span><\/strong><\/p>\n ## 1. Introduction<\/p>\n Plastic modular crate systems have become increasingly popular for creating underground storm water detention and attenuation systems. These lightweight, cost-effective alternatives to traditional concrete systems offer significant hydraulic and installation advantages. However, the fire safety implications of installing large quantities of thermoplastic materials in confined underground spaces have not been adequately addressed in current design standards or emergency response planning.<\/p>\n This paper identifies an emerging risk that sits at the intersection of civil engineering, fire safety, and emergency response, where insufficient knowledge and documentation may be creating unrecognized hazards for both the built environment and emergency responders.<\/p>\n ## 2. Background: Plastic Crate Storm water Systems<\/p>\n ### 2.1 System Description – Beneath car park slabs<\/span><\/strong> ### 2.2 Installation Scale ## 3. Fire Behaviour Characteristics of Thermoplastics<\/p>\n ### 3.1 Combustion Properties **Melting and Flow Behaviour:** **Heat Release Rates:** ### 3.2 Documented Suppression Challenges – Water application can cause surface crusting that prevents penetration to burning material beneath ## 4. Underground Fire Suppression Complexities<\/p>\n ### 4.1 Access Limitations **Physical Access:** **Equipment Deployment:** ### 4.2 Ventilation Considerations – Smoke and toxic gas accumulation in confined spaces ## 5. Current Knowledge Gaps<\/p>\n ### 5.1 Lack of Specific Fire Safety Standards Notable absence of: ### 5.2 Limited Incident Documentation ### 5.3 Emergency Response Protocol Deficiencies ## 6. Risk Assessment Considerations<\/p>\n ### 6.1 Ignition Sources ### 6.2 Consequence Severity ### 6.3 Exposure Assessment ## 7. Industry Perspectives and Bias Considerations<\/p>\n ### 7.1 Commercial Interest Influences **Concrete Industry Criticism:** **Plastic Manufacturer Positions:** ### 7.2 Need for Independent Assessment ## 8. Recommendations<\/p>\n ### 8.1 Research and Testing Priorities ### 8.2 Standards Development ### 8.3 Emergency Response Planning ### 8.4 Regulatory Considerations ## 9. Conclusion<\/p>\n The widespread adoption of plastic crate systems for underground storm water detention represents an emerging fire safety challenge that has received insufficient attention from the fire protection community. The combination of large quantities of thermoplastic materials in confined underground spaces, limited emergency access, and documented difficulties in suppressing plastic fires creates a potentially significant risk that is not adequately addressed in current design standards or emergency response protocols.<\/p>\n The fire safety implications of these systems require immediate attention through independent research, standards development, and emergency response planning. While commercial interests may influence available information about system performance, the fundamental fire safety questions must be addressed through objective assessment and transparent documentation.<\/p>\n Failure to adequately address these emerging risks could result in significant consequences for both public safety and emergency responders. The time to address these knowledge gaps is before widespread adoption makes remediation more difficult and expensive.<\/p>\n ## 10. Call to Action<\/span><\/strong><\/p>\n This paper calls for:<\/strong> The fire safety community must engage proactively with this emerging risk to ensure that the benefits of these systems do not come at the expense of public safety or emergency responder welfare.<\/span><\/strong><\/p>\n —<\/p>\n *This paper represents a preliminary assessment based on available information and professional experience. Comprehensive fire testing and research are needed to fully quantify the risks and develop appropriate mitigation strategies.*<\/p>\n Link to original abstract <\/a><\/strong><\/span><\/p>\n
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\nPlastic crate storm water detention systems consist of modular thermoplastic units, typically made from high-density polyethylene (HDPE) or polypropylene (PP), that are assembled to create void spaces for temporary water storage. These systems are commonly installed:<\/p>\n
\n– Under roadways and pavements<\/span><\/strong>
\n– In confined underground spaces with limited access<\/span><\/strong>
\n– Often adjacent to or integrated with building foundations<\/span><\/strong><\/p>\n
\nModern installations can involve:
\n– Hundreds to thousands of individual crate units
\n– Storage volumes ranging from hundreds to thousands of cubic meters
\n– Plastic material quantities measured in tons per installation
\n– Systems spanning large areas beneath critical infrastructure<\/p>\n
\nThermoplastic materials used in crate systems exhibit concerning fire behaviour characteristics:<\/p>\n
\n– Materials melt and flow when heated, potentially spreading fire
\n– Molten plastic can create flowing fire hazards
\n– Surface re-solidification creates crusts that trap burning material beneath<\/p>\n
\n– Thermoplastics can produce significant heat release rates when burning
\n– Large quantities represent substantial fuel loads in confined spaces
\n– Heat production can exceed the cooling capacity of conventional suppression systems<\/p>\n
\nResearch has identified specific difficulties in extinguishing plastic fires:<\/p>\n
\n– Some thermoplastics produce large fire balls when water is applied
\n– Foam application may be required but presents logistical challenges in underground confined spaces
\n– Re-ignition potential due to trapped burning material beneath solidified surfaces<\/p>\n
\nUnderground plastic crate installations present unique challenges for fire suppression:<\/p>\n
\n– Limited entry points for firefighting personnel and equipment
\n– Restricted movement within void spaces
\n– Potential structural integrity concerns during fire conditions<\/p>\n
\n– Difficulty positioning suppression equipment
\n– Limited hose deployment options
\n– Challenges in establishing adequate water supply<\/p>\n
\nUnderground fires involving plastic materials create additional complexities:<\/p>\n
\n– Limited natural ventilation for heat and smoke removal
\n– Potential for creating adverse pressure conditions that affect fire behaviour<\/p>\n
\nCurrent design standards for plastic crate systems focus primarily on:
\n– Structural load-bearing capacity
\n– Hydraulic performance
\n– Installation procedures<\/p>\n
\n– Fire safety performance criteria
\n– Emergency access requirements
\n– Suppression system design guidance
\n– Risk assessment methodologies<\/p>\n
\nPublic documentation of fire incidents involving plastic stormuwater systems is notably sparse, potentially due to:
\n– Recent adoption of these systems
\n– Incident reporting gaps
\n– Industry reluctance to publicize failures
\n– Lack of systematic incident tracking<\/p>\n
\nFire and emergency services may lack:
\n– Specific training for plastic infrastructure fires
\n– Pre-incident planning for underground plastic installations
\n– Specialized suppression techniques and equipment
\n– Understanding of unique hazards presented by these systems<\/p>\n
\nPotential ignition sources in underground environments include:
\n– Electrical equipment and wiring
\n– Vehicle fires in overlying car parks
\n– Construction activities (welding, cutting)
\n– Adjacent building fires
\n– Utility infrastructure failures<\/p>\n
\nThe consequences of fires in plastic crate systems could include:
\n– Structural damage to overlying infrastructure
\n– Long-duration fires difficult to extinguish
\n– Toxic smoke production in confined spaces
\n– Risk to emergency responders
\n– Potential for fire spread to adjacent structures<\/p>\n
\nFactors affecting risk exposure:
\n– Proximity to occupied buildings
\n– Integration with critical infrastructure
\n– Location relative to emergency service access
\n– Local environmental conditions<\/p>\n
\nAssessment of plastic crate fire risks must consider potential bias from:<\/p>\n
\n– Traditional concrete pipe and tank manufacturers may overstate plastic system risks
\n– Commercial interests in promoting alternative technologies
\n– Selective presentation of technical limitations<\/p>\n
\n– Potential understatement of fire risks
\n– Focus on installation and cost benefits
\n– Limited discussion of long-term safety implications<\/p>\n
\nObjective evaluation requires:
\n– Independent fire testing and research
\n– Unbiased risk assessment methodologies
\n– Transparent reporting of both benefits and limitations
\n– Input from fire safety professionals without commercial interests<\/p>\n
\nImmediate research needs include:
\n– Fire testing of plastic crate systems under realistic conditions
\n– Suppression effectiveness studies for underground plastic fires
\n– Toxic gas production assessment during combustion
\n– Structural behaviour analysis during fire exposure<\/p>\n
\nFire safety standards should be developed addressing:
\n– Design requirements for emergency access
\n– Suppression system specifications
\n– Installation location restrictions
\n– Risk assessment methodologies<\/p>\n
\nFire services should develop:
\n– Pre-incident planning procedures for plastic infrastructure
\n– Specialized training for underground plastic fires
\n– Equipment and tactics specific to thermoplastic suppression
\n– Coordination protocols with system designers and installers<\/p>\n
\nBuilding codes and standards may require updates to address:
\n– Fire safety performance requirements
\n– Installation approval processes
\n– Ongoing inspection and maintenance protocols
\n– Emergency access and egress provisions<\/p>\n
\n– Immediate research into fire behaviour of plastic crate systems<\/strong>
\n– Development of fire safety standards specific to these installations <\/strong>
\n– Enhanced emergency response planning and training<\/strong>
\n– Greater transparency from manufacturers regarding fire safety limitations<\/strong>
\n– Regulatory review of approval processes for underground plastic infrastructure<\/strong><\/p>\n
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