Fretwork | (NEW) The Basis for a Newsletter item for OPSS
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(NEW) The Basis for a Newsletter item for OPSS

(NEW) The Basis for a Newsletter item for OPSS

This is the draft of a long version article to post on our website – in the public area.

The next stage after identifying if there are more or better points to make is to write a short version to offer to OPSS as a Newsletter item.

 

Your comments welcome. Please respect that this is only shown on our members are and should be kept to ourselves at this time.

 

PJW

 

FRETWORK ITEM FOR OPSS NEWSLETTER.

 

We believe as a Group that a very simple statement of principle(s) is important and necessary to inform the debate on the Review.

 

The original FFR were drawn up in response to a precise and clearly defined

 

                                    RISK of

 

Principle 1:

IGNITION occurring in large articles with PolyUrethane foam filling and an outer textile cover. This generally meant upholstered furniture.

 

Analysis of the fires recorded the following characteristics:

 

Domestic dwellings.

First item ignited: foam filled upholstery.

Smokers “materials” were most often/always involved.

Fire apparent some hours after last human activity at the seat of the fire.

High incidence of death and severe injury, remote from the seat of the fire.

Babies and Children were particularly susceptible.

 

Scientifically this can be recognised as being due to the large amounts of Smoke and Toxic Fumes (STF) produced under the specific conditions:

 

Restricted air supply (a closed room),

Delayed ignition (up to 3 hours)

Sufficient material in the first item ignited (foam filled upholstery) providing sufficient smoke and fume to fill the entire house. (including bedrooms/upstairs where occupants were asleep).

 

Why was this a new phenomenon?

 

The PolyUrethane Foam that we know was a development by ICI in the 1950’s. A new manufacturing process that solved the toxic chemistry issue allowed industrial development and that coincided with demand for new materials.

The product could be made flexible and rigid. We are interested in PolyUrethane Flexible Foam or PUF. Its development included application as a new material for the Upholstery Industry.

 

Perhaps there is no more eloquent description than the Scientist in ICI responsible for the work:

 

‘Today you have soft seats all over the house; when I was a lad, you didn’t. They were too expensive, or they didn’t last, or the springs came through’

– Reg. Hurd, ICI chemist, working on flexible foams

 

Source: “ICI, the company that changed our lives” by Carol Kennedy. 2nd edition 1993 chapman publishing. (unauthorised quote).

 

In today’s terms we may fail to recognise how these lightweight materials transformed upholstery and, in coincident times to the rapid development of Television (another British invention), became part of the Focus Point of Modern Homes.

 

Does it matter?

 

PUF is a material with special properties

 

The FRETWORK Group includes companies who work in a regulatory control environment and that includes the storage, handling and use of PUF and the associated fire risks.

Anyone not familiar with these requirements should consult:

 

https://www.hse.gov.uk/plastics/storing-celluar-plastics.htm

 

 

 

 

 

 

 

 

Perhaps we should look no further than recent papers from McKenna and Hull to provide some context: “The fire toxicity of polyurethane foams” Fire Science Reviews (2016) 5:3 (without permission).

 

Quote.

Toxic products formed during flaming combustion of polyurethane foams.
In the UK, the rapid rise in fire deaths, in particular those from smoke toxicity, between the late 1950s and the early 1980s has been attributed to the rapid growth in low cost polyurethane foam furniture, with superior comfort and lower cost than the natural fillings that preceded it.

And

“Over this period there was a corresponding shift from the main cause of death in fires being attributed to “burns” to being attributed to “inhalation of smoke and toxic gases”.

End Quote.

 

Much more could be written about the fundamental shift away from traditional materials with all their problems.

 

The Article shows that the chemistry of PUF foams is understood in terms of estimating the amount of Carbon Monoxide and Hydrogen Cyanide likely to release during burning and in particular when there is a restricted supply of oxygen. It also discusses the calculation of the amount of specific toxic materials and their lethality. It should not be a great work to determine how much foam is needed to fill a domestic living space to the point of lethality. It would be a great assistance to future Consumer Safety if we had a reference amount in mind when we come to RISK ASSESSMENT for different Consumer articles.

 

We believe that this is in agreement with our “Principle 1” and in particular the risk attached to “Large items”.

 

But why is it a problem?

 

We also reference Fire and Materials. 2018;42:394–402: “Intrinsic flame resistance of polyurethane flexible foams : Unexpectedly low flammability without any flame retardant by Hoehne, Hanich and Kroke from 2017.

 

From data in this article, we can compare and contrast PUF in the same way we would compare textile fibres and we are thus able to evaluate the “Naturally flame-retardant materials” key component, wool in the same way.

 

Key Point:

No tests exist to define the materials used in comparison to the Risk Assessment as in Principle 1. The Risk Assessment is ONLY respected by the wording of the present FFR.

Therefore, we have no way of comparing different materials or informing the development of new or novel materials.

 

It is clear that without a required performance and test procedure a failure to define this risk would completely contradict the risk assessment that lies at the heart of the present FFR and its success over the last 30 years.

 

We would caution at this point that chemically there are strong similarities between Wool fibre and PUF (and hence their burning characteristics – including toxicity!!!). Comparing Empirical chemical structure, we may see that the natural wool with a “typical” composition of C72H118N18O12S contains more Nitrogen and Sulphur than PUF with C17H16N2O4.

 

It is important to understand the differences that are easily identified so we start with the basics of Textile flammability:

 

Thermal properties of commonly used Textile fibres

Including comparative data for TDI PUF

Fibre Regain

% Moisture

LOI

% oxygen

Melting Point oC Ignition Temperature oC Self-ignition

Temperature oC

Thermoplastic behaviour
Acrylic 1.5 18 215 – 255 250 515 chars
Cotton

Cellulose

8.5 19 Not relevant 350 400 chars
Polyamide

Nylon

4.0 20 215 420 450 melts
Polyester 0.4 22 250 390 508 melts
Polypropylene 0 19 145 350 – 370 390 – 410 melts
Viscose

Regenerated Cellulose

          chars
Wool 20 25 Not relevant 325 590 chars
TDI PUF 0 16 Thermal degradation begins at 260  
 

 

 

 

How should we compare different fillings?

 

There are tests for the ignition performance of different fillings.

PUF is always tested against BS 5852 methods and all foam must meet a crib 5 composite test for Upholstery and Mattresses.

Other types of fillings and mattress fillings especially are treated differently.

Upholstery “other fillings” are tested to variations of BS 5852 with smaller ignition sources in some cases.

Mattress fillings comprised of PUF must perform identically to upholstery PUF.

 

THERE IS NO TEST REQUIRED THAT IS DEFINED BY THE RISK ASSESSMENT IN Principle 1.

 

What differences can we identify?

 

From the table we can see that the (Moisture) Regain is quite different between Wool and PUF.

Wool can absorb up to 40% of its weight in moisture without actually FEELING damp/wet.

PUF is prone to hydrolysis by moisture.

Controlling the humidity of wool samples in burn test is critical.

Such levels of moisture are highly effective in terms of flame retardancy.

All the water must be driven off before ignition can occur and that amount of energy is significant.

 

The thermal behaviour is also important.

 

Wool doesn’t melt and has an ignition temperature of 325oC.

PUF starts to decompose and release toxic gasses at ca. 260oC.

For this reason, the small ignition sources used for textiles and the upholstery composites are relevant.

The present FFR identified a severe crib 5 test being suitable for the PUF.

The worst-case scenario for the open flame ignition source 1or match test is made according (ONLY) to the present FFR to be a non-flame retarded PUF (that is illegal in use).

 

It is also important to record that the smoulder (cigarette) test or ignition source 0 in BS 5852 has always been recognised as important because it replicates the slow exothermic reaction producing copious smoke and toxic fumes (STF) described in Principle 1.

 

Physical form is important.

 

Textiles are particularly prone to ignition due to their 2D form (a thin sheet of material). Air is available at the surface on both sides.

PUF in comparison is always considered in this context as a “BLOCK”. It has a 3D form. It should also be noted that it has excellent THERMAL INSULATION properties.

 

THIS IS UNDOUBTEDLY THE BASIS FOR THE USE OF A COMPOSITE TEST FOR IGNITION PROPERTIES ACCORDING TO BS 5852.

Those who make these tests know well the effect seen on the textile and the foam below in BS 5852 ignition source 0 tests.

 

MUCH ACADEMIC WORK HAS BEEN DONE ON THE BEHAVIOUR OF PUF IN IGNITION AND BURNING BUT THERE REMAINS NO SINGLE TEST THAT REPLICATES THE RISK DEFINED IN PRINCIPLE 1.

 

WOOL would seem to be an ideal material to replace PUF but Textile Technology smiles at this point when the flexibility and resilience of PUF is assessed and we can compare that to the use of FULLING STOCKS in textile manufacture.

Has anyone (recently) made a durability of performance test on wool as a filling material?

Replacements for PUF are difficult to identify and physical characteristics are as important as chemical composition

 

What is the alternative?

 

The specific chemistry that provides an alternative to the performance required of a flexible foam filling AND the burning behaviour risk is not readily apparent. We have described how its physical form, similar to textiles, will ensure that ignitability must always be addressed in any risk assessment.

 

It is highly likely that alternative, new or novel approaches to materials used in upholstery manufacture will be able to completely replace PUF in all aspects but, provided they can demonstrate avoidance of the identified risk, they must be able to find a place in the market

 

Principle 2                           Testing

 

It is not unusual for Risk Assessment to identify a Burning Behaviour requirement for textiles due to their physical nature. What makes them essential also defines the risk: Fine physical form surrounded by plenty of air is a good basis for all materials to burn and what makes the chemistry of fibres perfect for the purposes they fulfil also makes them easily ignited.

 

Foams are very similar in physical character and, not surprisingly, similar in burning behaviour. A good foam will represent a 5% of polymer surrounded by air in a 50 kg. per cubic metre upholstery foam.

 

Both benefit in suitability for purpose from having low weight. The upholstery industry similarly uses textile fibres as a high bulk, low weight web in addition to foam. Modern upholstery and the consumer have benefited from these aspects in terms of cost and availability. Little is normally said about the environmental benefit of using synthetic filling materials nor the (huge) environmental impact of natural materials they replaced.

 

The original FFR used the test methods developed through different requirements that became BS 5852. Little is written about exactly which tests should be used but we can describe quite simply and recognise the importance this choice has in the success of the FFR in reducing fire death and casualty figures:

 

PUF fillings are tested in combination with a flame retardant textile cover with a crib 5 test (ignition source 5).

The outer textile actually used is tested with a match flame style (ignition source 1) open flame in combination with a FLAMMABLE PUF (not ignition resistant) filling.

And a smoulder source with a cigarette (ignition source 0) in combination with filling actually used.

 

The first point to emphasise here is the lack of need to test the propensity of the PUF to produce smoke and toxic fumes. That is dictated by the chemistry.

It is also defined by the FFR.

 

The need to prevent ignition occurring was understood and the original requirements of the FFR with respect to PUF addressed that point.

 

Subsequent analysis of fire data has been used to confirm that this approach was successful.

“A statistical report to investigate the effectiveness of the Furniture and Furnishings (Fire) (Safety) Regulations 1988, Greenstreet Bearman 2009”

 

The testing of the PUF as a component to be used is critical to the Risk Assessment and this can be explained in 2 very informative pictures:

The first picture (taken on a smart phone) on the effect of a charging malfunction of a modern smart phone on an item of UK manufacture PUF filled upholstery.

 

The second picture is from a mattress and was recorded by Staffordshire Fire Service (see: https://www.staffordshirefire.gov.uk/news/latest-news/near-escape-involving-tablet-charging-overnight/ ). Their report is, we believe, entirely in line with our FFR Principle 2.

In case it is not immediately apparent we should emphasise that the lack of ignition:

 

Does validate the stringent test performance required by the FFR for PUF.

Does equate to ‘limited’ SMOKE AND TOXIC FUMES (STF).

It does NOT equate with the POTENTIAL amount of STF if the foam had ignited/been completely consumed.

The objective of ignition resistance for PUF is crucial.

The event will not contribute to Death and Causality fire statistics.

 

Ignition resistance is important when the Risk Scenario is considered and not the same thing as a reduced rate of burning.

The problem then follows as to how we take the component testing and performance approach adopted by the FFR and turn that to Final Product performance requirements without losing the specific Risks identified in the FFR.

 

…..and another thing?

 

The next step must be to evaluate the position as described and ascertain if there are other issues than just following on from what “went before”.

 

What are the next steps?

 

It would not be the same if FRETWORK could not ask some questions:

 

We can identify several issues that have bene highlighted in the current review process and place them in the context of the basic principles. They may be applied in all aspects of the present FFR to be reviewed. Here are some of the things we have seen thus far:

 

1       The difference between Upholstery and Mattresses.

 

The opportunity to try different materials and achieve the declared objectives of this will be easier if the original Risk attached to PUF is clearly defined. It would be prudent to maintain the principles of Principle 1 but, without the use of PUF and its necessary performance requirements, alternatives will be easier to identify.

The position of the bedding articles in the FFR is a clear demonstration of this.

The use of the so-called naturally flame-retardant materials is possible when the testing regime as defined in the present FFR, Schedule 2 Part 4 are applied.

Only the PUF component is defined outside this deviation. The present review is dedicated to maintaining safety standards and they surely cannot rely on applying the mattress requirements as described to upholstery – or can they?

 

It is important to recognise that the testing requirements described in the Match test are made (for many reasons) over a flammable i.e. a non FFR complaint foam. The present FFR requirements for PUF define that the Outer cover used in UPHOLSTERY will be match resistant while the combination test according to Schedule 2 Part 4 for MATTRESSES are actual materials and not the flammable foam used in the UPHOLSTERY match test.

 

It is clear that the Risk identified in the concerns for a growing “Foam filled Mattress” market as set out at the OPSS Birmingham meeting will be allowed to be taken into the present regime for mattresses without ensuring that the specific Risk originally attached to PUF is not maintained?

 

2       Risk Assessment must be properly applied and not a catchall.

 

There are a wide variety of articles included in the scope of the present FFR where questions must/should be asked as to how they came to be included.

Before describing these issues we must make clear that a proper evaluation of Risk and Consumer Safety is necessary but the test described by our 2 Principles must be applied in all cases. It would not be a good outcome if e.g. legal challenge were required to define these issues under the GPSR process?

 

The easiest and clearest example of this comes with the group of items relating to Baby Products. Some of these items will inevitably contain relatively large amounts of PUF and the case described in Principle 2. should be applied. On the other hand there are definitely a wide range of items that are too small to include sufficient PUF to fill a dwelling with STF.

 

There are different methods available and indeed in use. The Toy Regulations refer to different test methods to the FFR but then the Risk assessment is different.

 

3       The opportunity to use “naturally flame-retardant materials”

 

A lot has been written in various places around this term. Unfortunately, most sources fail to qualify their use of it with relevant testing details to ensure that a proper context is applied. This, of course, raises the issue of unsupported claims and we have heard on several occasions that such materials find use in mattresses and similar items.

This is one item that would fail the test of our Principle 2.

We must ask when will someone take the trouble to compare the burning decomposition behaviour of wool in comparison to PUF???

It is likely that a comparative risk assessment would place Wool and PUF in the same category!!!

 

All Stakeholders need to start the process of Risk analysis and determining the best testing regime to ensure product safety for their products and their Market sector and their consumers. It will certainly be a process where questions may be asked about how we treat different materials.

 

What is important?

 

Risk assessment will be applied by all manufacturers and suppliers of final articles and this could leave the very specific risk identified in the FFR that will easily be left behind in any changes.

 

That would negate the benefits created by the FFR.

 

The Specific Testing Regime described by the FFR must be understood and made a continuing requirement.

 

This approach will allow New or Novel systems of manufacture to be able to establish their suitability provided they can establish the ABSENCE of the specific Risk established in the FFR.

Peter Wragg
Peter Wragg
pjw@fretwork.org.uk
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