Fire Safetyon

Polyurethane Foam

Japan Urethane Industries Institute
初版：2008 年 3 月

1. Recent trend of fires
According to the recent White paper on fire and disaster management, the number of death infires increases in the aged people and the infants in recent years. It is estimated that their fate isseriously affected by the physical activities on the refuge behavior after realizing the fire. About
60% of the death number in residence fires is of aged people over 65 years old. It is concernedthat the deaths in residence fires will
Number of death in Fire, 2006
increase following to the ageing of the(except for arson and suicide)society. In the process of the death at
Unknown
fires, the delay of the escaping
Number of death;
Others7%
1,475 persons
reaches about 60%, in which the cases
4%of delaying to realizing, surrounded
Bruise,with fire and smoke when realizing, no
Fracture of
CO gasbone, etc.
escaping way are counted most. It
Poisoning &0%
Suffocationshows the importance of the42%
countermeasure for the fire extinguishat the initial stage of the fire and theBurn
fire prevention.
47%
The cause of death in fires isM. Internal Affairs &mostly of the poisoning by carbon
Communications
monoxide, and suffocation, followed byburn.
Many polymer materials are used in the modern buildings, the harmful gases other than carbon
monoxide are reported to generate in the fires. It is estimated that carbon monoxide and otherharmful gases generated from various materials interrupt the refuge behavior at the early stage inthe fires. The amount of the combustion product generated from the materials depends on thekinds of the materials and the combustion condition.

2. Flammability of polyurethane and polyisocyanurate foams
Polyurethane foams are applied to the bedding
and furniture as mattress and pillow, sponges andinsulation and structural materials in buildings,
refrigerators etc.
Recently there appear occasionally news and anarticle reporting that hydrogen cyanide, a harmful gas,is generated from polyurethane foams in residence
fires and as if the deaths were caused bypolyurethane foams. However any other various harmful
gases are generated in the fires, especially carbon
monoxide is widely and mostly generated in case ofimperfect combustion of every combustible material aswood, textiles and plastic materials. Polyurethane foams
are not denied to generate hydrogen cyanide in case offires. Hydrogen cyanide has high toxicity in fact, but it isactually not clear what kind of and how much harmful
gases are generated in the real fires.
A study is enforced on the influence of hydrogencyanide contained in the combustion gas frompolyurethane foam to the obstruction on the refuge
behavior in comparison with other materials existing in theliving space in the combustion test under the assumptionof the fire.

“Gas hazard assessment” is enforced withTest Apparatus
fireproof performance test, heat buildup test and（Construction Ministry Notification No.1231)
others for the fire preventive materials in theBuilding Standard Law of Japan. “Gas hazard
Thermo regulator
Agitation chamber
And Fanassessment” is to evaluate the requirement to
Thermo regulator
And Fan
Testing chamber
the material “not to generate hazardous smoke
Exhaust temperatureand gas in case of evacuation” in article 108 – 2in the Building Standard Law Enforcement
Eight rotary
Exhaust blower
Heating furnace
tread cagesOrder , is to judge the influence of the complex
Propane gas
combustion gas to guidance on evacuationand heater
Mixerpumpduring fires. Under theflowmeter
Exhaust flowmeter
assessment arranged
Exhaust unit
pumpby Japan Urethane
Secondary air
Primary air
Industries
Institute,polyurethane foam forgeneral use gives
longer time to the incapacitation than red lauan, the standard material,
and meets the assessment requirement even though it generates
hydrogen cyanide. The result confirms that polyurethane foam is not a
product to obstruct evacuation action remarkably in comparison with the（ 財 ） 建 材試験 セン ター
wood which is a building material used for long time and widely, andother materials existing in the living space.

3. Flammability test of polyurethane and isocyanurate foams
It is not clear what kind of and how much hazardous gas are generated in the actual fires
because every fire is in different situation as quantity of inflammable materials, construction of thebuilding involved etc. and the combustion behavior is too complicated to identify the components inthe combustion gas generated in the fires.
Generally there are two evaluation methods for combustion gas toxicity;
1) animal test where animals as rat and mouse are exposed directly to the gas concerned,2) the analysis of the amount of decomposed products and combustion products, and then isevaluated in comparison with toxicology data reported in the literatures.
The mouse “Gas hazard assessment”, which is introduced in this report, is a method classified
in the category 1) above mentioned. The harmful gases generated in the fires are essentiallyconsidered most desirable to be evaluated with the information obtained from the organism mostclose to the human as the complex combustion gas. In Japan “Gas hazard assessment” with using
mouse is applied to confirm the hazardous component and to verify the validity of toxicity
evaluation with gas analysis result. The materials, which meet the requirements of the heat buildup
test others and “Gas hazard assessment” under the fireproof performance test, are regarded tofulfill the requirement of the quality for the fire preventive material by the Building Standard Law ofJapan, and hardly generates the products to obstruct the evacuation activities. Many polyurethane
products (mainly polyisocyanurate products) are approved as fire preventive materials.
The followings are confirmed of the versatile polyurethane foams and other materials with the“Gas hazard assessment” enforced under Japan Urethane Industries Institute.
••

Every polyurethane foam (flexible polyurethane foam, rigid polyurethane foam andpolyisocyanurate foam) tested clears “Gas hazard assessment”
Polyurethane foams release hydrogen cyanide in burning. However hydrogen cyanide isgenerated from not only polyurethane foams but all polymeric materials containing nitrogen as
woolen insulation materials and surface decorative wooden building materials when they burn.
The origin of hydrogen cyanide generation is not limited in polyurethane foams.

•The concentration of hydrogen cyanide generated in combustion of polyurethane foam is lower
than that of surface decorative wooden building materials and wool (clothes etc) which aregenerally in living space.
The concentration of hydrogen cyanide is considered to be strongly uncorrelated with the timeto the incapacitation.

< Gas hazard assessment results >1514131211109876543210Pass

Time to incapacitation of mouse

(min)

合格

Wool clothes

Surface decorative wood

Polyester fabrics

Polypropylene fabrics

Polyisocyanurate foam

Flexible Polyurethane foam

不合格Failure•

Rigid Polyurethane foam
04080

120

160200Hydrogen cyanide concentration (ppm)
The time to the incapacitation is clearly correlated with the concentration of carbon monoxide. Itshows low value with high value of carbon monoxide concentration.

< Gas hazard assessment results >1514131211109876543210Pass

Time to incapacitation of mouse(min)合格
Surface decorative wood

Polyester fabrics

Polypropylene fabrics

Polyisocyanurate foam

Flexible Polyurethane foam

不合格

Rigid Polyurethane foam0•

Wool clothes

Failure•

0.4
0.8
1.2
1.6
Carbon monoxide concentration (%)

2

It is necessary to discuss on the risk of the complex combustion gas, dominantly of carbon
monoxide, other than hydrogen cyanide, among various combustion products in the fires. It issuggested by the fact that polyester fabrics and polypropylene which release low amount ofhydrogen cyanide show similar level of the time to the incapacitation to polyurethane foam.

Not only polyurethane foams but organic materials areflammable. Under combustion they release chemically asphyxiant
gases as dominantly carbon monoxide, and irritant gases as
aldehydes and hydrogen chloride, further lack of oxygen happens
due to raise of carbon dioxide and loss of oxygen. We live insurrounded with flammable materials as wood and fabrics, withtaking advantage of their feature well. It may not exaggeration to saythat we cannot live under elimination of these flammable materials
in daily life. Therefore the fire extinguish in beginning and safe
evacuation are important before the fire extends to these flammablematerials. Wooden materials are widely used in not only
construction and exteriors of houses but interiors, furniture andfixtures in naked condition.
Meanwhile polyurethane foams are rarely used in naked as interior
and exterior materials, but used with any surface material as interiormaterial with high fire protection performance. They are considered
to be in lower risk of hazard of combustion gas in the actual application. Polyurethane products asother plastics don’t ignite by themselves, but catch fire at close origin of fire. After catching fire they
may be in danger of expansion of the combustion as other organic materials, so it is important tokeep away the fire.

4. Lastly,
Japan Urethane Industries Institute makes every effort to improve technology further, anddevelop much low combustible products and continuously perform the educational activities toeliminate wrong understanding on combustion safety of polyurethane foams. JUII works on thebelow educational activities, also.
· Storage of polyurethane raw materials and foam products under appropriate storage
circumstance and temperature.
· Observance of processing manuals and handling standards· Appropriate guard for fire protection, notice on fire prohibition, and arrangement of fire
extinguisher· Thorough observation of fire handling ( confirmation andrevision of processing manuals)· Understanding material safety data sheets (MSDS)· Understanding processing sites of polyurethanes· Appropriate disposal of waste liquid of raw materials andpolyurethane foam waste

For further information, please refer to Guidance on Fire Safety Assessment of Polyurethane
Foams, edited by Japan Urethane Industries Institute.

Japan Urethane Industries Institute is organized of Japan Urethane Foam Association and Japan
Urethane Raw Materials Association and consults on the programs as to maintain and improvesafety and health, to work on environment issues, to spread high quality products, to consult on savingenergy and public relations.
Home page: http://www.urethane-jp.or.jp

Japan Urethane Industries InstituteJapan Urethane Foam Association

Japan Urethane Raw Materials Association

2-17-1, Nishishinbashi, Minato-ku, Tokyo,

2-8-11, Nishishinbashi, Minato-ku, Tokyo,

105-0003, Japan

105-0003, Japan

Phone: +81-3-6402-1252

Phone: +81-3-3591-1855
All right reserved and reproduction prohibited
printed in March 2008