Temperatures of touchable surfaces - a personal burn hazard

Issue
Non-working surfaces of many domestic appliances reach high enough temperatures to present a significant risk of causing burn injuries. Contact with the hot surface may be intentional, such as turning a control knob, or inadvertent, such as brushing against the side of an appliance. The side walls of some electric toasters have been found to exceed 200 degrees Celsius¹.

The problem of dangerously high surface temperatures on domestic appliances has been recognised for many years². Many children have suffered burns injuries after touching glass oven doors and the sides of toasters. Older people have also been burnt and complaints about dangerously hot surfaces on domestic appliances continue to be recorded after more than twenty years³. The system which has failed to deal with this problem needs to be examined. Several prosecutions by local authority Trading Standards Departments are currently awaiting Judicial Review.

Principle
There is no reason to specify different surface temperature limit values for similar surfaces and product applications. The surface temperature above which burning occurs when a hot surface is touched does not depend on the type of product but primarily on the material and surface texture and on the period of contact with the hot surface. So it is desirable to harmonise surface temperature limit values in all product safety standards. This approach is supported in the latest authoritative guidance⁴.

Objective
The purpose of this paper is to examine whether the current law is being breached and whether changes need to be made to the voluntary standards to help manufacturers meet their legal obligations and reduce their exposure to prosecution and claims for damages. Recommended surface temperature limit values are given at Appendix ll.

Law
All appliances must satisfy statutory safety requirements. Failure to do so places the manufacturer, importer and distributor of unsafe products at risk of prosecution. Investigations have taken places and cases brought by many local authority Trading Standards Departments⁵ over recent years against suppliers of appliances that have excessively hot surfaces. Such action is usually reactive, following a complaint.

Difficulty in proving cases "beyond reasonable doubt" present a major obstacle mainly because of the failure of many standards to provide appropriate guidance on hot surface temperatures. It should be noted that producers are also at risk of being sued if a defect in their product causes an injury. However, injuries are usually not sufficiently serious to warrant such expensive and protracted action.

It is an offence to supply or place goods on the market which fail to meet the requirements of the Consumer Protection Act 1987. British law⁶, ⁷ has adapted European Directives⁸ by regulations covering the safety of all consumer products.

Safety regulations in which surface temperature is an issue include electrical⁹, gas¹⁰ and "general" products¹¹. The regulations transposed European Directives 73/23, 90/396 and 92/59/EEC respectively. A product must satisfy essential (safety) requirements and be a "safe product" as defined by the General Product Safety Regulations 1994 based on the definition of "safe" in the 1987 Act.

Although the problem of hot surfaces affects a whole range of domestic appliances and should therefore be dealt with horizontally as a general issue, the following study looks at electrical equipment and electric toasters in particular.

Regulation 5 of the Electrical Equipment (Safety) Regulations 1994 requires electrical equipment to be, inter alia:

safe;
made in accordance with good engineering practice regarding safety i.e. harmonised European standard; and
satisfy the safety objectives - which are identical to those in the Directive.

All three conditions must be satisfied, i.e. the electrical equipment must -

1) be "safe"
Section 19 of the Consumer Protection Act 1987 defines "safe" in relation to products as meaning, inter alia, such that there is no risk, or no risk apart from one reduced to a minimum, that the goods, their use or assembly, whether immediately or after time, will cause the death of or any personal injury to, any person.

"Safe" in the Electrical Equipment (Safety) Regulations has the same meaning but also covers the risk of death or injury to domestic animals and damage to property. However, it excludes any risk arising from improper installation or maintenance of the equipment or for uses for which it was not made.

2) be made in accordance with "good engineering practice regarding safety ";
This is best represented by the appropriate harmonised European Standard; and

3) satisfy the "safety objectives".
The principal elements of the safety objectives are detailed in Schedule 3 to the Electrical Equipment (Safety) Regulations 1994. Paragraph 2 deals with protection against hazards arising from the electrical equipment and 2(b) requires that temperatures which could cause a danger must not be produced.

Presumption of conformity
Regulation 6 states that electrical equipment which satisfies the safety provisions of harmonised standards shall be taken to comply with the requirements of regulation 5(1) unless there are reasonable grounds for suspecting that the electrical equipment does not so comply. There must be "reasonable grounds" if the equipment is not safe!

There is no presumption of conformity and the supply of such equipment is illegal.

Example
A domestic electric toaster can be used to illustrate what the law requires with regard to the safety of all electrical appliances within the scope and subject to the Electrical Equipment (Safety) Regulations 1994, in particular Regulation 5. Some toasters have been found to have side walls whose temperatures reach over 200 degrees Celsius and many exceed the limits recommended in standards dealing with surface temperature.

Question: Can such a toaster meet the three requirements above and therefore satisfy the law?

Answer: No, for the following reasons -

a) It is not "safe"
An electric toaster which produces very high temperatures on its outer surface, sometimes exceeding 200 degrees Celsius, which can be touched under normal conditions of use, cannot satisfy the requirement of being "safe". Results of laboratory tests¹² show temperature levels which will burn the skin even on brief inadvertent contact.

b) It is not made in accordance with good engineering practice regarding safety.
Only one of the three requirements that can be claimed to be satisfied is that it is made in accordance with good engineering practice regarding safety as represented by the harmonised standard BS EN 60335-2-9. However this standard has now been accepted as being defective in this respect by the European Commission¹³. It does not address the risk in relation to non-working surface temperatures and therefore fails the Article 9 Safeguard procedures and cannot provide a presumption of conformity with the Directive. The Commission has requested the standards body CENELEC¹⁴ to deal with this shortcoming and in the meantime manufacturers are advised to carry out risk assessments on their products.

c) It does not satisfy the "safety objectives".
There is a significant risk of a person incurring a burn injury when using such a toaster with dangerously hot side walls and this risk has not been reduced to a minimum contrary to the definition of "safe" in the Act and Regulations. Many toasters produce temperatures which present a danger, contrary to the safety objectives in Schedule 3 paragraph 2(b) of the Regulations.

Design
General guidance is provided in EN 292¹⁵ on the safe design of equipment to deal with hazards including thermal hazards. EN 292 provides manufacturers with the strategy necessary to comply with European legislation in particular the Machinery Directive 89/392/EEC. The standard advocates avoiding or reducing as many of the hazards as possible by suitable choice of design features e.g. by avoiding, as far as possible, thermal effects [Clause 3.6.1].

This is a useful guide for manufacturers of consumer products also. Identifying hazards and assessing risks at the design, production, distribution, use and decommissioning stages should be carried out at an early stage in the development of new products. The risks should be addressed by eliminating, reducing, isolating or controlling hazards before adopting less effective methods such as warnings.

Standard
BS EN 60335-2-9¹⁶ is the harmonised European standard for toasters and similar appliances and can be said to represent what regulation 5(b) means by "principles generally accepted within the Member States as constituting good engineering practice in relation to safety matters". Being a standard developed and agreed by all interested parties, no other specification can claim such universal acceptance.

However, this harmonised standard fails to address the burn hazard caused by high surface temperatures, it is therefore deficient and in need of urgent amendment. It is also defective in that it excludes "the use of appliances by young children or infirm persons without supervision" [Clause 1 Scope]. Many appliances covered by the standard are used by children and infirm persons and the standard should at least recognise this fact. The hazards, principally electrocution and burn, but also mechanical, toxicity and flammability, should be identified and the risks assessed. Electrical safety may be effectively dealt with but the other hazards are clearly not.

Clause 11.1 of the standard's general requirements¹⁷ states that "Appliances and their surroundings shall not attain excessive temperatures in normal use" but there is no guidance on how to measure the temperature of the outer surfaces of the toaster or what the upper limits are.

Factors
Factors to be considered when assessing the risk of a burn caused by a hot surface are:

the temperature of the surface;
the material of which the surface is made; and
the period of contact between skin and surface.

The English language version of EN 563 was prepared under the direction of the Personal Safety Equipment Standards Policy Committee (PSM/39). Members of this committee included representatives from professional and trade associations, testing bodies and the Consumer Policy Committee of BSI. The standard was produced as a result of international discussions in which the UK took an active part. EN 563 was approved by CEN (European Committee for Standardisation) on 14 June 1994 and has the status of a British Standard. [National foreword, page i and annex NA].

The method of assessing hot surfaces on existing machinery in informative Annex D.2.2.1 states that the persons who may touch the surface have to be identified and those who may come into contact with it, e.g. children in the home, must be included.

Informative Annex D.2.3 states that the surface temperature limit value will be between 60 and 66 degrees Celsius and for household machines this may be set at the lower end because of the risk of burning the skin of children or elderly people.

The upper temperature limit for accidental 1 second contact with a painted metal surface is therefore 83 degrees Celsius. Temperatures higher than this will result in superficial partial thickness burns where the epidermis is completely destroyed but the hair follicles and sebaceous glands as well as the sweat glands are spared. Higher temperatures will result in deep partial thickness burns where a substantial part of the dermis and all sebaceous glands are destroyed and only the deeper parts of the hair follicles or the sweat glands survive. Still higher temperatures will result in whole thickness burns when the full thickness of the skin has been destroyed and there are no surviving epithelial elements.

Although voluntary, and compliance with standards does not of itself confer immunity from legal obligations, standards provide the best available technical interpretation of the law. They are drafted by technical committees comprising all interested parties including trade and industry, professional organisations and consumers bodies.

EN 13202:2000 with the aid of EN 563 provides guidance to technical committees on how to set surface temperature limit values in product standards. EN 563 is based on scientific research whereas EN 13202 is based on mathematical calculation and reasonable conclusion. As Clause 1 states, the standard is intended to apply to all products where hot surfaces cause a risk of burning and which can be touched by healthy adults, children, elderly and physically disabled people. It also applies to products used in any enviroment, e.g. workplaces, the home, etc.

Surface temperature limit values
Authoritative documents which deal with the contact burn hazard are:

BS 4086:1966¹⁸
BS EN 13202:2000
PD 6504:1983¹⁹
BS EN 563:1994²⁰

BS 4086:1966 Clause 3 specifies maximum temperatures for surfaces to be touched when using the appliance, e.g. handles and knobs and for other heated surfaces including parts of heating or cooking apparatus that get hot incidentally because of their position but are not regarded as normal working surfaces and where contact could happen accidentally. Such temperatures should not exceed 105 degrees Celsius.

BS EN 13202:2000 is intended to help users assess the burning risk and select appropriate protective measures and to assist technical committees address the issue when drawing up standards.

PD 6504:1983 provides medical information on human reaction to skin contact with hot surfaces. It recommends in its foreword that lower temperatures than those specified in BS 4086 should be adopted for touchable surfaces where possible and appropriate, where such temperatures can be shown to be economically justified and technically practicable. It also states that when further research data are available, BS 4086 will be reviewed urgently and revised as necessary.

BS EN 563:1994 the harmonised European standard which deals with the temperatures of touchable surfaces was mandated by the European Commission to support the requirements of EC Directives. [Foreword Page 2]. The principal Directives are those which deal with safety at work, however it is necessary to consider this standard when assessing the safety of products used elsewhere, including appliances used by consumers in their homes.

BS EN 563 applies within the field of application of EN 292 the safety of machinery but the data can also be used in the development of standards for specific machinery where, as a result of a risk assessment, temperature limits are required. The standard applies to the healthy skin of adults. [Scope, Page 3]

Conclusions

An electrical appliance, including an electric toaster, which produces temperatures on its surface sufficiently high to injure a person making contact with it, under normal or foreseeable conditions of use, is not "safe" nor does it meet the safety objectives laid down in the Regulations. Its supply is therefore illegal;
Guidance on surface temperature limits, BS 4086 and PD 6504 has been available to manufacturers of such products for over thirty years but widely ignored;
The hazard of burns produced by high surface temperatures on mainly workplace machinery has been recognised however and suitable guidance produced in the form of a harmonised standard EN 563. This is now made specifically relevant to consumer products with the publication of BS EN 13202:2000;
The involvement of the Consumer Policy Committee of BSI in the preparation of EN 563 and references in the standard implies that consumers' interests were being considered as well as those of operators of machines in the workplace;
When assessing the safety of an electrical appliance, regard must be had to the temperature reached by its outer surface which can be touched;
The present law is adequate to deal with dangerously hot surfaces on appliances but many of the standards which interpret the legal requirements are defective in that the burn hazard is not recognised or not dealt with effectively;
The standards for all appliances which produce high temperatures on their non-working surfaces need to address the burn hazard, preferably by cross-reference to the new horizontal standard covering the specific issue;
The horizontal standard BS EN 13202:2000 in line with EN 563 has been developed for consumer appliances and should be universally adopted;
Pending a resolution to the above, BS EN 13202:2000 should be adopted as the expert guidance on the subject of surface temperatures for all domestic appliances;
The Judicial Review should consider all the relevant matters discussed above.

Appendix l

Commission Opinion (2000/C 104/07)
This Opinion within the Low Voltage Directive 73/23 concerns the Article 9 LVD safeguard clause procedure. It acknowledges a shortcoming in the harmonised standard EN 60335-2-9 dealing with surface temperatures of toasters and similar appliances. The safety objectives laid down in Annex l, s 1(d) and 2(b) to Directive 73/23 require electrical equipment to be designed and manufactured so as to ensure that protection against hazards in relation to surface temperatures is assured.

CENELEC has been requested by the Commission to ensure that the hazard is adequately addressed in a revised standard. Meanwhile, manufacturers may need to carry out risk assessments to ensure their equipment is designed and manufactured to reduce the risk as much as is reasonably possible.

Appendix ll

Recommended maximum surface temperature limit values
The following limit values are based on the harmonised standards -

BS EN 13202:2000 Ergonomics of the thermal environment - Temperatures of touchable hot surfaces - Guidance for establishing surface temperature limit values in production standards with the aid of -
EN 563: 1994 Safety of machinery - Temperatures of touchable surfaces - Ergonomics data to establish temperature limit values for hot surfaces

Materials/time-temp*	1 sec	4 sec	10 sec	10 min	8 hr
uncoated metal	65	58	55	48	43
painted metal	83	64	55	48	43
enamelled metals	74	60	56	48	43
ceramics, glass, stone	80	70	66	48	43
plastics	85	74	70	48	43
wood	110	93	89	48	43

Time	Contact	Part
1 sec	accidental contact	oven doors, toaster sides
4 sec	parts held for short periods	knobs, switches
10 sec	parts continuously held in normal use	handles
10 min	prolonged use	handles
8 hr	continuous use	handles

* temperatures quoted are in degrees Celsius for the materials used and for likely contact time.

The data are based on healthy skin of adults.

Significantly lower temperature limit values apply when considering the safety of children, elderly people and those with physical disabilities particularly when making unintentional contact with appliances having hot non-working surfaces.

The following table indicates upper burn threshold limit values for various surfaces for an unintentional contact period of 1 sec. Temperatures quoted are in degrees Celsius.

Materials/time-temp	1 sec
uncoated metal	70
heavily coated metal	95
ceramics, glass, stone	86
plastics	94
wood	140

References

1 Author’s personal records
2 OFT Complaints records to 2000
3 Author’s personal records
4 BS EN 13202:2000 Ergonomics of the thermal environment - Temperatures of touchable hot surfaces - Guidance for establishing surface temperature limit values in production standards with the aid of EN 563
5 Lancashire, Leicestershire, Lincolnshire, Solihull, Southampton, Southwark etc. (personal records)
6 Consumer Protection Act 1987
7 European Communities Act 1972
8 Machinery Directive 89/392/EEC
Electrical Equipment Directive 73/23/EEC
Gas Appliances Directive 90/396/EEC
General Product Safety Directive 92/59/EEC
9 Electrical Equipment (Safety) Regulations 1994 [SI 3260]
10 Gas Appliances (Safety) Regulations 1995 [SI 1629]
11 General Product Safety Regulations 1994 [SI 2328]
12 Personal records
13 Commission Opinion (2000/C 104/07)
14 European Committee for Standardization
15 EN 292-2: 1991 Safety of machinery - Technical principles and specifications
16 BS EN 60335-2-9 Safety of household and similar electrical appliances Section 2.9 Toasters and similar appliances
17 BS EN 60335-1 Safety of household and similar electrical appliances Part 1. General requirements
18 BS 4086:1966 Recommendations for - Maximum surface temperatures of heated domestic equipment
19 PD 6504:1983 [BSI published document] Medical information on human reaction to skin contact with hot surfaces
20 BS EN 563: 1994 Safety of machinery - Temperatures of touchable surfaces - Ergonomics data to establish temperature limit values for hot surfaces

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