Green and Safe Materials: Compatibility or Conflict? José L. Torero BRE Centre for Fire Safety Engineering The University of Edinburgh.

Green and Safe Materials: Compatibility or Conflict?

José L. ToreroBRE Centre for Fire Safety Engineering

The University of Edinburgh

Issues in Fire Safety Engineeringo Integration of FSE to building designoEducational needsoDevelopment of new tools

o Structural modellingo Fire dynamics

oAnalysis of new technologiesoConstructionoMaterials

oRevisiting of existing knowledge

IntegrationoFire Safety affects every aspect of a

buildingDefinition of Space• Egress• Structure• Smoke management

Building Services• Alarm• HVAC• Water

Security• Access• Monitoring

Energy & Sustainability• Insulation• Building Fabric

Optimization

oCurrently fire safety is trying to integrate to other disciplinesoAvoid unnecessary redundancyoAvoid unnecessary costoAvoid unnecessary complexityoAvoid inefficiency

Evolution of EducationoEducating professionals that understand

the Fire Safety Strategy as part of the Built EnvironmentoProvides answers before the questions are askedo Integrate/optimises systems

oAllows the Architect: oAchieve what he/she wantsoCircumvent problemsoAvoid excessive engineering

How do Green Objectives Affect this?

oRequires further optimizationo Increases complexity

oLimits optionso Integration

oChanges nothing!

Example: Green MaterialsoNatural MaterialsoNo Fire RetardantsoHigh thermal resistance/thermal massoLow embedded energyoRecyclable, etc.

oChanges nothing!

o Is there any incompatibility?o...just makes our job a bit more

complicatedo...just requires us to better engineers

Need to Understando Small scale tests

used to gather information about material

o Tests defined implicit performance

o Presence of retardants make unnecessary any further detail

Implicit PerformanceoMade understanding unnecessary

oRetardants solved the problemo Standard test certified the problem was solvedo The engineer did not have to think

oWe stopped thinkingoCould not justify benefit of retardantso Environmental/Health cost became the single

variableoWe lost the war for fire retardants before it

started

Further Demandso Lower thermal conductivity requirements are

displacing non-flammable insulationo Energy conservation requirements are making

flammable cavities ubiquitouso Reduction of embedded energy is requiring a

reduction of protective layers, etc.o Changes nothing!o ...If we had not forgotten how to think!

How do we take control?

oWe start thinkingoQuantitative cost/benefit analysisoWe need to scale up performance – benefitoWe need provide effective protection – costoWe need to understand environmental

impact - cost

Scaling up Performance- Stages

o IgnitionoGrowthoFire interacting with smokeoFlashover (secondary ignition)oPost flashoveroBurnout

Complexityo Ignition

oSimplestoNo-combustionoNo heat feedback

from the flame

oComplexityo Implies models of the

gas and solid phase

Water

Losses

Convection

Radiation

Heat Transfer

Degradation Chemistry

Heat Feedback (glowing)

Mass Transfer

Pilot - Gas Chemistry

We just have a more complicated problem...

oChanges nothing!oOnly if we are good enough engineers...

....are we?

Could it be that my subject is neither man nor fish but a gawky representative of a new species? This species could have as its discipline the understanding and thence the bringing of a modicum of control to the hitherto intractable quality called "Safety", a word whose aura must surely extend beyond ourselves to our fellows, to those that follow us and even to mankind. And in the shadow of Safety there is always Risk which comes strongly into the light when the emphasis of our studies turns to the adventurous journey of mankind through time, space and such as might lie between. In pursuit of gaining the measure of Safety and Risk we could well find ourselves ranging unashamedly from Physics to History, why even beyond. For will we not be concerned with bringing what has been called "Acts of God", amongst which Fire has had such a terrible ranking, into the regime under man's control? What impudence, but if true it would be New Variation on an Old Theme indeed!

Concluding paragraph of the Inaugural Lecture presented by Professor D. J. Rasbash on November 14th, 1974 at Appleton Tower, The University of Edinburgh.