Commission de sécurité des consommateurs

In January 2006, a petition was received and registered by the Commission under the number 06-006. It was filed by a consumer who received severe burns to the face when using an alcohol gel, which, according to the manufacturer, was specifically intended for the lighting of all types of fire and for the filling of the small dishes used in certain table cooking appliances.  When asked by the Commission, the manufacturer stated that they had been informed about the accident and had taken corrective measures. Since the Commission had received no other petitions of the same type, the case was closed.

In June 2007, in an article in the newspaper Le Figaro, Professor Wassermann, in charge of the unit for the treatment of severe burns victims at the Cochin Hospital in Paris, called for a ban on sales of methylated spirits, claiming that "over 75% of victims of household accidents treated in severe burns units are hospitalised as a result of a problem lighting a barbecue."  

Concerned by this figure, the Commission decided, at its plenary session on 13 September 2007, to draw up a draft recommendation into the safety of methylated spirits, and more generally of other types of firelighter products marketed in liquid or gel form, especially with regard to the risk of burns.

InVS estimated the number of burn injury accidents caused by methylated spirits to account for around 1 in 10 000 everyday accidents listed in the EPAC[1] database for the 2002-2005 period. Simply applying this ratio (which, given the size of the initial sample, leads to a high degree of uncertainty) to the 4 450 000 theoretical hospital admissions gives an estimation of 450 admissions per year to casualty departments in public hospitals in France for burn injuries caused by methylated spirits.

In summer and autumn 2007, the Commission carried out a survey of severe burns units in metropolitan France. This showed that an average of seven patients burnt by methylated spirits are admitted to each severe burns unit every year.

Applied to all the severe burns units in France, this average gives an annual estimation of around 140 admissions to severe burns units as a result of accidents caused by methylated spirits, which makes up between 5 and 6% of annual admissions. It has been observed that the number of admissions is especially high between June and September. Nonetheless, for the doctors and nurses asked, the number of accidents does not appear to make it necessary to distinguish methylated spirits from other especially accident-causing flammable products such as petrol or white spirit.

When the accident data from both health care networks are added together, the overall estimate obtained is that 585 victims of burns caused by methylated spirits are admitted for hospital treatment per year in France. Of course, this figure only makes up a part of the real number of accidents, since any patients who resort to self-medication or who are treated outside the hospital system are not taken into account.

In addition, the degree of severity of methylated spirits burns appears to be greater than that for all everyday accidents taken together, with around 20% of patients hospitalized as opposed to 11% for all everyday accidents taken together. Most of the time, it is the upper parts of the body, the chest, arms and hands, the face and neck, that are affected. Children are estimated to make up a third of all victims.

There is at first sight an abundant supply of firelighter liquids and gels, but in reality this can be boiled down to two categories of products:

1. Liquid methylated spirits

Methylated spirits is a colourless liquid chemical preparation, readily miscible with water. Its main constituent is 90° or 95° alcohol with a foul taste, obtained from the residues of distillation of plant products used for the production of ethyl alcohol, or ethanol[2]. This alcohol is then denatured by the addition of various substances in quantities that are defined in accordance with regulations, in order to make it permanently unfit for human consumption.

Within the European Union, several denaturing procedures are recognized[3].

Another 95° or greater denatured alcohol, based on neutral rectified alcohol obtained directly from the distillation of plant products, is marketed as a surface cleaning product under the name of 'household' alcohol or 'superior' household alcohol. According to the manufacturers, its denaturing formula may differ slightly from that of methylated spirits. Bactericides or perfumes are often added to make it more effective and more pleasant to use.

Of these two preparations, only methylated spirits is defined as a fuel, although in physical terms both alcohols behave identically when they burn.   From a regulatory viewpoint, they are therefore both classified as 'highly flammable'. This is because the temperature at which they produce vapour which, at a certain concentration, is likely to catch fire when in contact with a naked flame, called the 'flash point'[4], lies between 0°C and 20°C. As its French name ('alcool à brûler', literally 'burning alcohol') shows, methylated spirits is mainly sold as a 'clean' fuel, because although it has a strong smell, it is virtually odourless when it burns and hardly gives off any smoke. In addition, this alcohol does not impart a taste to food that is heated directly or indirectly by it.  In France, as in Spain and Germany, the name 'burning alcohol', based on the use of the product rather than on its chemical composition, is very commonly used.  In the English-speaking countries, it is more often called meths, methos, methylated spirit(s)' or 'denatured alcohol'. However, methylated spirits is also sold for its many household uses (cleaning, removal of paint, glue and varnish, antifreeze, insecticide, etc).

Because it is so cheap, denatured ethanol continues to enjoy high sales in France (2.8 million litres), and it is a cleaning product that is considerably cheaper to purchase than other products.

Finally, it is worth emphasising that the recent appearance of ethanol burners is currently boosting the use of denatured ethanol as a fuel.

2. Ethanol-based firelighter gels

Ethanol gels are products based on neutral rectified alcohol and, in addition to ethanol, contain bitters, isopropanol, combustion accelerators with very low flash points such as acetone[5], gelling agents based on cellulose ethers and colouring agents.

The main selling point of this type of preparation is its safety when in use compared with liquid firelighter products, especially with regard to the risks of accidental spillage and flashback.

These are mixtures of aromatic or paraffin hydrocarbons, commonly called petroleum 'hydrolysates' , 'light distillates', or 'petroleum fractions', obtained from the distillation of crude oil. Kerosene is the most frequently used fraction in these products, which also include all the so-called 'lamp oils' and paraffin, which can be found either in the solid state or in dissolution.

Colourless or slightly yellow in appearance, petroleum hydrolysates can be recognized by their hydrocarbon odour, which varies according to the aromatic substances they contain, and by their slightly oily appearance.

Since their flash points are over 55°C (between 67°C and 85°C), they are not considered to be highly flammable from the regulatory viewpoint. They are harmful if swallowed and an irritant for the respiratory tract.

On the firelighter market alone, all firelighters taken into account, petroleum hydrolysates today account for 45% of sales.

IV. REGULATIONS THAT APPLY TO METHYLATED SPIRITS AND FIRELIGHTER PRODUCTS

There are no regulations that are specific to methylated spirits and firelighter gels.  They come under directives 67/548/EEC and 1999/45/EC (amended) which lay down requirements relating to the marketing of dangerous substances[6] and preparations, especially with regard to labelling.

 

However, they make no provision for:

−    the position on the label of symbols, hazard warnings and advice on use, and especially their visibility in comparison with the product trade name;

−    the compulsory inclusion in the hazard warning of the comment: "not to be used to relight a fire or embers".

−    for preparations, a general obligation to specify on the label the composition or the main constituents that have an effect on the hazardous nature of the product[7];

−    the compulsory presence of a tear band, which would improve the safety of the packaging, especially in shops, by making it possible to spot packages that had been opened and which, if not correctly reclosed could be a source of danger (spillage both in and outside the shop, ingestion by a child, etc);

−    maximum amounts of unit-dose packaging according to the hazard class of the product.

Since 1988, the manufacturers of such substances and preparations, classified as hazardous or containing, in certain proportions, hazardous substances, if intended for professional use, must in addition provide employers and self-employed workers with a safety data sheet. This obligation is covered under article 31 of regulation (EC) No. 1907/2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) and the content of the sheet is specified in Appendix II of this regulation.

 

The regulation does not provide for the delivery of this sheet to non professionals. With regard to preparations that are intended exclusively for the use of the general public and as long as they "are provided with sufficient information to enable users to take the necessary measures as regards the protection of human health, safety and the environment", the data sheet need not be supplied to downstream users or distributors[8].

With a view to facilitating trade while protecting human health and the environment, a new European regulation, which will replace directives 67/548/EEC and 1999/45/EC is in preparation. It will in particular be based on the Globally Harmonized System of classification and labelling of chemicals (GHS).

This standard defines requirements with regard to safety, performance, packaging and labelling, and lays down testing methods for all types of firelighter, whether solid, liquid, paste or gel, which are used to light solid fuels for barbecues and grills.

This standard does not apply to methylated spirits, which is not a firelighter, nor to by-products sold as firelighters. This is because Article 1 ('scope') specifies that: "…the use of highly flammable liquids (except for stabilised formulations) is specifically excluded from the scope of this standard, since their use for barbecues is considered to be extremely dangerous".

This has obviously had no effect on the marketing of denatured ethanol-based gels as a firelighter.

The NF EN 1860-3 standard therefore defines a certain number of recommendations and test methods for 'readily lightable'[9] products in contact with a flame (Article 3.2), referring to:

−    for liquid products, the flash point, which must be 55°C or over, which according to the Order of 20 April 1994, characterises not very flammable substances, for which it is not compulsory to place a specific hazard symbol on the label;

−    for paste or gel products, to a number of behaviour criteria when burning (articles 4.1.4 and 4.2.1.2) which guarantee the safety of the product when in use: "…the firelighter must light easily, and burn uninterruptedly, without producing smoke, sudden deflagration, sparks, spluttering, detonation, seepage or explosion, from the moment of lighting to its extinction. In contact with a naked flame…the firelighter must neither burst into flame, nor create a flashback, nor catch fire inside the container."

With respect to the packaging, this must be equipped with:

−    a "childproof closure" tested according to the method specified in standard NF EN ISO 8317 (Article 4.3.3.1); 

−    a measuring cap which must be firmly fixed to it (Article 4.3.3.2); 

−    a protection system that prevents leakage (Article 4.3.3.3).

Like the regulations, the standard does not stipulate the need to mention the composition of the principal hazardous constituents of the product on the label, the presence of a tear band or a maximum capacity for unit-dose packaging.  It does not deal with the risk of accidental spillage, as distinct from the risk of leakage, nor with the risk connected to the soaking of a cloth with the firelighter product, even though this is a potential cause of accident if the cloth is brought near a source of heat or of ignition.

Standard NF EN 1860-3 stipulates that liquid firelighters must be packaged in containers fitted with a "childproof closure" tested according to the method specified in standard NF EN ISO 1860-3, which are defined as follows (Article 2.3): 

Of the thirty firelighter products examined by the Commission during its investigation, none carried a mention of their compliance with the NF EN ISO 8317 standard. After investigation, it appears that the expressions 'childproof safety cap' or 'childproof protective cap' displayed on the labels of certain products[10] designate caps that are designed by cap manufacturers to meet the requirements of the NF EN ISO 8317 standard without their necessarily having been tested on the bottle on which they are intended to be used. Without these tests and despite this information, consumers therefore only have limited assurance that the closure system on the product they buy is really childproof. At the worst, there is a risk that it will lull consumers into a sense of false security if they should use such 'safety caps' to close bottles into which hazardous products have been transferred.

The Commission entrusted the CNPP with carrying out a number of laboratory tests, with the aim of analysing the hazardous nature of around ten firelighter products representative of the market, on the basis of physical and chemical analyses and simulation exercises.

The tests were deliberately carried out without reference to the requirements and test methods used by the public authorities and standardisation organisations to describe firelighter products, since none of the firelighter products were described by the manufacturers and distributors as conforming to the NF EN 1860-3[11] standard. The Commission essentially based its tests on the typology of the most frequent accidents as indicated by its own inquiries and testimony received from healthcare professionals.

The flash point is the only indicator used in regulations to determine the hazard class of firelighter products. This indicator was therefore measured in the laboratory and compared with the data mentioned on the safety sheet for the ten products. Other values were also measured on the basis of standardised experimental protocols: the fire point to know at what temperature a product can burn continuously, the self-ignition temperature, the calorific value, i.e. the energy efficiency of the product, and the viscosity. Other observations, although not standardised, were carried out on the colour and height of flames, as well as the combustion time of a 75 ml quantity of product in an open dish.

The results (cf. Appendix no. 1) give a contrasting picture. They show in particular that:

−    methylated spirits and household alcohol show an equivalent burn risk;

−    the term 'gel' is applied to products of greatly differing viscosity;

−    although firelighter gels in principle contain a smaller proportion of denatured ethanol, some of them have an identical or even lower flash point than liquid alcohols;

−    methylated spirits and ethanol gels release half as much energy as petroleum hydrolysates;

−    the fact that the product is in the form of a gel does not alter flame colour. Flames produced by ethanol-based firelighters are always less visible than those produced by petroleum-based products;

−    combustion times for the various products are similar, with the exception of gels based on petroleum hydrolysates.

In addition,

−    the production of vapour, as measured by the volatility index is considerably slowed down by gelation. Gels are at least 7 times less volatile than liquids, and volatility is even sometimes impossible to measure using the standardised protocol. However, this characteristic does not appear to be connected only to the viscosity of the product;

−    products in gel format have a higher self-ignition temperature.  In the absence of a naked flame, hydrocarbon-based products catch fire at the lowest temperature, around 230°C, whereas alcohols and ethanol gels need a temperature of over 400°C to self-ignite. As gels, the self-ignition temperature of ethanol- or petroleum hydrosylate-based products is higher (by 10 to 80°C) depending on their composition.  Presumably, the presence of water and the gelation process (solution or emulsion) may delay the release of the basic flammable constituent;

−    in an open dish, ethanol gels formed flames that were slightly less high than liquid alcohols. On the other hand, flames formed by the petroleum hydrosylate gel were higher and the blaze, which is rapid, produces spluttering[12].

The ten firelighter products then underwent three types of tests aimed at studying their behaviour in typical accident situations.

In the first phase, the test aimed to determine the angle at which bottles tipped over and the amount of product spilled. The test was carried out with the original full bottle, having been subjected neither to impact nor deformation[13], with the stopper removed, both with and without the flow restrictor.

Since the bottles were relatively uniform in size (24 to 27 cm high and with a base diameter of 7 to 8 cm), the tipping angle measured was between 12 and 15°. This value is in accordance with stability recommendations laid down in several standards concerning cooking appliances, electric lamps, etc.

The amount of product spilled depends partly on the viscosity of the product. It was around 165 ml for methylated spirits, 130 ml for petroleum products (20% less) and 50 ml for the gel. However, it essentially depends on the presence of a flow-reducing stopper. This reduces the diameter of the neck of the bottle from 23 mm to 3 to 4 mm, and reduces the volume spilled by 95% to 100%. This flow reducer was not present on bottles of methylated spirits.

Such a stopper does not have only beneficial effects on flow. For instance, for the most viscous gels, the reducer tends to fly out of the neck of the bottle as soon as the pressure exerted to get the product out of the bottle is too strong, with the possible risks of splashing and flashback towards the bottle.

In a second phase, tests involving the tipping over of full bottles next to burning embers in an open fire clearly showed that liquid products set fire to embers placed at a distance of over one metre, more precisely as far away as 1.60 m for alcohols and 1.20 m for petroleum products. The gels do not spill when the bottle is knocked over, and therefore cannot set light to the embers.

 

This time, the products were deliberately spilt first onto an open fire of burning embers, and then onto an enclosed fire (fireplace made of blocks of aerated concrete sealed by a sheet of rock wool). As a result of these tests, two distinct patterns emerged:

−    liquids (alcohols and petroleum products) caught fire explosively, producing flames over 2 m high for alcohol and from 1.5 to 2 m high for petroleum products, whether the fireplace was open or enclosed;

−    alcohol- and petroleum-based gels caught fire gently and non-explosively, producing flames three times smaller, i.e. 30-50 cm high in an open fireplace, and 70-85 cm high in an enclosed fireplace, except for the petroleum gel, whose behaviour was invariable (flames 20-40 cm high).

In a real situation, trying to relight hot embers with a gel, which cannot be thrown on but needs to be placed on the fire, requires a person to get much closer to the embers than with a liquid product. Despite the results observed, this practice should not be encouraged, and the gain in safety obtained should be considered within this context.

This test aimed to determine the risk of burns in the event of ignition of cotton cloth with a polyester warp, previously soaked in alcohol or a firelighter product, and varying the amount and duration of drying time. It was observed that:

−    during the first quarter of an hour, alcohols and methylated spirits-based gels appear to be more dangerous than petroleum products. For petroleum products, however, the flame must be applied for over two seconds in order to bring about the ignition of the cloth;

−    after one hour of drying, alcohols, due to their high volatility, are less dangerous than methylated spirits-based gels;

−    petroleum-based liquid products and gels follow the same pattern whatever the amount and duration of drying applied to the cloth.  An exposure to the flame of two seconds is required to ignite the soaked cloth.

An analysis of the labelling of the selected products was carried out in comparison with the applicable regulations and with the results of the tests carried out by the CNPP. It emerges that, overall, all the products tested are in conformity with obligations concerning the labelling of hazardous products, except for three points:

−    the size of the prescribed symbols never covers 10% of the area of the label;

−    the symbols and captions used are not always those laid down by Schedule VI of the Order of 20 April 1994;

−    hazard warnings, which are compulsory, are not always included, especially for gels.

For the rest, according to the Commission, the labels, while in accordance with regulations, could be improved regarding a number of points:

−    hazard symbols are never printed on the visible side of the product, next to the trade name;

−    labels are sometimes hard to read due to the choice of colours, the layout of messages and visual images, the size of characters, or the large number of hazard warnings and advice;

−    when it appears on the label, the non-compulsory phrase "not to be used on a hot fire or embers" does not specifically stand out among the advice for use, even though this is one of the major causes of burn injury accidents due to firelighters.

 

On the safety data sheets for the products, the flash point is generally lower than shown by the tests, except for the gels where it is obviously overestimated. This gives the impression that they are safer than they actually are. Information about other data varies, especially with regard to self-ignition temperature, heat of combustion and viscosity, despite their effects on the way the product burns and on the risk of accidental spillage.

Based on all these tests, the Commission has attempted to characterise the overall hazard level of each of the products tested by classifying them into three categories: 'not very hazardous', 'fairly hazardous', and 'very hazardous'.

This evaluation was then compared with an evaluation based on the prescribed classification of hazardous products based on the flash point of products, and, for some of them, on the boiling temperature.

The table below compares these two evaluations: [TRADUCTION DU TABLEAU:  Products   Type of product    Liquid denatured ethanol    Petroleum hydrolysate   Denatured ethanol gel   Petroleum hydrolysate gel    Prescribed classification   CSC classification]

  

 Blue: not very hazardous      Yellow:  fairly hazardous     Orange:  very hazardous

Thus, contrary to what the regulations on hazardous products and the NF EN 1860-3 standard imply, firelighter gels, including those based on denatured ethanol, are, if used in identical conditions, among the least hazardous products, due to their behaviour with regard to risk of spillage and splashing on hot fires. They appear to be safer than liquid products and in particular than petroleum hydrolysates, which are in principle considered to be the least hazardous by the regulations.

As a result of this investigation, the Commission considers that denatured ethanol, in its liquid form, should not be used in a household context as a fuel or firelighter. This is because its extremely hazardous nature when used for lighting fires and charcoal-based barbecues is clearly established, as it is for all liquids classified by regulations as 'readily flammable'. This justifies the decision of professionals to exclude them from the scope of the NF EN 1860-3 standard of July 2003 relating to firelighters for the ignition of solid fuels.

It also appears that existing regulations concerning hazardous substances and preparations do not make it possible to avoid the majority of accidents caused by the use of firelighter products, since such accidents are mostly connected to inappropriate use, clumsiness or lack of attention.

Fortunately, there is unanimous agreement in principle among professionals, the public authorities and the representatives of consumer associations auditioned by the Commission on the need to implement specific measures liable to limit the use of denatured ethanol as a fuel or firelighter. Measures such as changed product appearance, new marketing choices by distributors or improved information for consumers by the public authorities, which would essentially aim to redirect consumer demand towards firelighter products that are better adapted to such use, do not appear to pose any particular problem from an economic, technical or legal viewpoint to those who would implement such measures.

 

Whereas the lack of specific and precise epidemiological data on the etiology of burns entails, in particular, gaps in knowledge about burns caused by the use of denatured alcohol of the methylated spirits type and by firelighter products;

Whereas denatured ethanol and firelighter liquids and gels today make up 90% of sales of firelighter products used by private individuals and catering professionals;

Whereas tests carried out by the Commission demonstrate the hazardous nature of denatured alcohol, in its liquid form, when it is used as a fuel or as a firelighter for solid fuels;

Whereas current legislation is limited with respect to the identification, labelling, and packaging of hazardous substances and preparations, as well as with respect to information for consumers about the risks and safety precautions against the risk of burns and poisoning when using such products;

Whereas, on the basis of auditions carried out by the Commission, there exists a consensus between the public authorities and the professionals concerned about the importance of implementing measures aimed at avoiding the use of liquid denatured ethanol as a firelighter and of inciting consumers to use only firelighter products that are in accordance with standard NF EN 1860-3; 

Whereas elementary safety precautions should be taken by consumers when lighting fires in fireplaces, barbecues and all types of fire with the help of a firelighter product of whatever kind;

Whereas the Commission considers it necessary that a more thorough investigation into the safety of solid firelighter products be carried out, and that the drawing up of a draft recommendation on the safety of ethanol burners is in progress.

−    the promotion of the use of cleaning products and firelighter products that use alternatives to denatured alcohol, by means of consumer information, shop displays and attractive pricing policies;

−    voluntary cessation of marketing of products sold under the designation of methylated spirits, without prejudice to sales of denatured ethyl alcohol as 'household' alcohol used as a cleaning product;

−    the exclusive marketing of denatured ethanol for use as a fuel under the designation of combustible 'paste' or 'gel', in single-use dishes of 10 cl maximum capacity.

−    to import, produce, package or market, for use as a firelighter, only products included within the scope of standard NF EN 1860-3 and complying with it;

−    not to use descriptions that refer to the safety or protection of children when describing closure systems used on bottles of hazardous products, and especially those based on denatured ethanol or petroleum hydrolysates, unless such packaging meets the requirements of standard NF EN ISO 8317.

−    make it compulsory to provide information about the main constituents and their proportions on the packaging of hazardous products for household use;

−    make it compulsory to place prescribed hazard symbols on the visible part of the labelling of hazardous substances, near the trade name;

−    classify as a mandatory 'S'-type warning information about the danger of relighting fires or embers by means of a firelighter;

−    limit, for private individuals, the maximum capacity for unit-dose packaging of hazardous products, especially those classified as extremely or readily flammable, which should not exceed one litre;

−    make the presence of a tear band compulsory on closures for packaging of hazardous products.

−    take into account the risks of product spillage;

−    determine in a more restrictive manner the minimum viscosity of products described as gels and pastes;

−    while waiting for a change in regulations, improve the identification, labelling, and packaging of firelighter liquids and gels, as well as information for consumers about the risks of burns and poisoning and safety precautions to be taken when using such products;

−    include tests on the toxicity of by-products from the combustion of firelighters (smoke, soot, ash, etc) within the standard.

Lastly, in order to complete these recommendations, the Commission has decided on the principle of drawing up a draft recommendation on the safety of solid firelighter products.

Measurement carried out	Product no.1:	Product no.2:	Product no.3:	Product no.4:	Product no.5:	Product no.6:	Product no.7:	Product no.8:	Product no.9:	Product no.10:
Identification	99.5% ethanol	99.7% ethanol	Fraction      C9-C13	Fraction       C8-C20	Fraction C9-C14	93% ethanol	98% ethanol	97% ethanol	91% ethanol	Fraction       C9-C14
Flash point (°C)	16,5 +/- 2	15,5 +/- 2	67,5 +/- 2	85 +/- 2	78 +/- 2	15 +/- 2	17,5 +/- 2	13,5 +/- 2	15,5 +/- 2	67 +/- 2
Fire point (°C)	25,5 +/- 2	24 +/- 2	76 +/- 2	100 +/- 2	93,5 +/- 2	Not determined	Not determined	Not determined	Not determined	Not determined
Self-ignition temperature (°C)	412	411	> 500	214	240	> 500	496	414	427	339
Higher calorific value (MJ/kg)	23,995	27,385	50,455	47,325	46,91	23,600	17,210	25,925	22,685	41,215
Volatility index	1,373	1,557	0,051	< 0,008	0,013	not measurable	0,0095	0,205	0,184	not measurable
Viscosity at – 10°C  (mm²/s)	22,2	22,6	15,8	solid at -10°C	45	14188	2400	3890	8390	not measurable
Viscosity at 20°C (mm²/s)	5,9	5,0	1,2	5,5	5,5	4100	1094	1998	2866	not measurable
Viscosity at 30°C (mm²/s)	not measured	not measured	not measured	not measured	not measured	3725	753	1415	2085	not measurable
Combustion in dish
flame colour	Pale orangey-yellow tip and blue base no visible smoke		Brilliant orangey colour visible smoke			Pale orangey-yellow tip and blue base no visible smoke			Blue base and bright orange tip with no visible smoke	Brilliant orangey colour
height of flame (cm)	Mean: 25 Maximum 35	Mean: 25 Maximum 35	Mean: 30 Maximum: >40	Mean: 25 Maximum 40	Mean: 30 Maximum: >40	Mean: 20 Maximum 25	Mean: 15 Maximum 25	Mean: 20 Maximum 30	Mean: 20 Maximum 30	Mean: 35 Maximum 50
combustion time	14’ 05	14’ 09	14’ 48	18’ 43	16’41	16’21	13’11	16’05	16’35	10’58