This recommendation has reference to
the decree of 22 October 1969 on smoke flues in housing
the decree of 24 March 1982 on the ventilation of housing
the Consumption Code - L.224-1, L.224-4, R.224 - 4 & R.224-7 to R.224-12
the decree of 2 August 1977 on the technical and safety rules applying to gaseous fuel installations and appliances in housing.
the decree of 5 April 1988 on generators & the thermal characteristics of housing
the Règlement Sanitaire Départemental (departmental health regulation) & its draft amendment
the appeal no. 95-071
1 - The Direction Générale de la Santé (General Directorate for Health at the State Secretariat for Health) brought before the Committee on 5 July 1995 the problem caused by some systems redistributing hot air produced by inserts, by open hearths, or by closed hearths. Consumers most frequently use the insert system (see definitions in the appendix) strongly recommended by installers given its greater efficiency in terms of heat production. Insert systems generally operate on wood or coal but some use gas. Whatever type of hearth and fuel is used, the problems likely to arise are the same however.
2 - The referral was drafted precisely as follows:
‘I wish to inform you that the last meeting of the ‘Prevention of carbon monoxide poisoning’ working group of the Conseil Supérieur d'Hygiène Publique de France (Higher Council for Public Hygiene in France), held on 15 June 1995, addressed inter alia the problem caused by the appearance on the market of systems mechanically extracting hot air from closed hearths.
These systems draw in the hot air under the cowl of inserts or closed hearths installed in decorative fireplaces, then redistribute it to other rooms in the house. This creates a negatively pressurised zone surrounding the connection of the closed hearth to the smoke flue (under the cowl) which can cause flue smoke to be partially drawn in and redistributed in the other rooms. This polluted air is likely to present abnormally high levels of carbon monoxide placing home occupants at risk. Given the potential risks this type of system appears to present, would you please examine this matter and determine whether it is opportune to give an opinion on the subject’.
|3 - Heat generators (inserts, for instance), whatever fuel is used, are not concerned by the referral, which concerns exclusively systems redistributing hot air.|
4 - Such systems comprise an electric fan, conduits carying hot air around the house and hot air openings. They are designed to blow into bedrooms or other secondary rooms air heated, in general, in the main room, the living room.
5 - Systems redistributing hot air appeared on the market approximately 15 years ago, around 1985. Out of a global number of 2.5 million installations, 10% to 20% (inserts or closed hearths) are thought to be equipped with a system redistributing hot air, i.e. 250 000 to 500 000 units.
6 - Some systems can be bought at DIY stores at varying public prices: the price of the ventilation kit is approximately FF500 to FF4 000; with conduits and gratings the installation price may reach FF5 000 to FF10 000.
7 - Gas hearths represent a market share of approximately 1%, just like coal hearths or mixed hearths. As for inserts and closed hearths using wood as the fuel, about 180 000 are sold each year, making them the main items sold.
8 - The Committee questioned by mail the professionals concerned, namely:
HBH INTERNATIONAL, whose advertisements drew the attention of the Ministry of Health,Fédération des industries mécaniques (federation of engineering industries),
Syndicat national de la tôlerie et de la tuyauterie industrielle (national union of steel plate work and industrial piping),
Union syndicale des constructeurs de matériel aéraulique, thermique, thermodynamique et frigorifique (UNICLIMA—union of manufacturers of ventilation, heat, thermodynamic and refrigerating equipment),
Centre technique des industries aérauliques et thermiques (CETIAT—technical centre for ventilation and heat industries); Centre scientifique et technique du bâtiment (CSTB— building sector scientific and technical centre),
Centre technique des industries mécaniques (CETIM—technical centre for engineering industries); Union climatique de France (union of climatic engineering companies),
Syndicat des constructeurs de petites turbines hydrauliques (union of manufacturers of small water turbines),Association technique des industries thermiques et aérauliques (ATITA—technical association of heat and ventilation industries),
Syndicat de la construction métallique de France (union of constructional steel work companies in France),
Fédération nationale du bâtiment (national building federation),
Syndicat national de l'isolation (national insulation union),
Groupement interprofessionnel des fabricants d'appareils d'équipement ménager (GIFAM—interprofessional grouping of manufacturers of household equipment appliances), at its request.
9 - The technical survey highlighted the following data:
With a hot air redistribution system, the room where the hearth and the air intake are situated may become negatively pressurised, while the bedrooms or other secondary rooms (into which the air is blown) may, on the contrary, become positively pressurised; these differences in pressure depend on the characteristics of the fans used and the ventilation circuit (air circulation), but also on the characteristics of the house and its ventilation system (air tightness of the facades, insufficient gap under doors to allow air circulation, air exhausted from the house...),
these pressure differences can cause poor combustion leading to the production of carbon monoxide which will be recycled in the rooms into which the hot air is blown—most frequently bedrooms where people may well be poisoned.
10 – Indeed, although the volumes blown out by these systems are identical to the volumes drawn in, it has been observed that the following problems can arise during operation of the system:
pollutants are recycled from one room to the others (tobacco smoke passes from the living room to the bedrooms, for instance) leading to passive smoking,
the house's ventilation system may be disturbed (the bedrooms become positively pressurised which leads to a lack of fresh air in these rooms), causing headaches, breathing difficulties, and problems for asthma sufferers.
the hearth draws badly because the living room is negatively pressurised. This can have an effect on carbon monoxide (CO) production, which may be lethal. Yet the fight against pollution, and more specifically against CO, are public health priorities.
11 - As these risks exist, specific measures should be taken to protect consumers better.
A –Lack of legal rules for systems redistributing hot air:
12 – The Committee has noted that no specific text currently exists for most of these systems.
B – Incidence of texts applying to generators and controlled mechanical ventilation
13 - On the contrary, texts of a regulatory or legislative character apply to similar equipment and, once analysed, can serve as a guide in recommending solutions for systems redistributing hot air.
14 - Indeed, at this time, gas-fired systems redistributing hot air (heat generator + hot air redistribution system) are subject to specific rules since they must comply with the requirements of directive 90/396/EEC. Similar provisions exist for fuel-fired appliances.
15 - Also three Documents Techniques Unifiés (D.T.U. - see appendix) lay down the rules for installing gas heat generators, and inserts and hearths using wood or coal as the fuel:
D.T.U. 61.1 which specifies the rules for implementing the decree of 2 August 1977 on gas-fired appliances,
D.T.U. 24.2 2 ‘Fireplaces fitted with a closed hearth or an insert using only wood as the fuel’,
D.T.U. 24.2.3 ‘Fireplaces fitted with a closed hearth or an insert designed to use solid mineral fuels and wood as fuels’.
16 - Reference can also be made to the acceptance guide for a controlled mechanical ventilation installation, or inspiration can be found in the regulations on gas-fired appliances, which appear more advanced.
17 - The ‘Controlled mechanical ventilation installation acceptance guide’ lays down in particular the checking of ‘air passages’ between rooms as they avoid one of the rooms becoming negatively pressurised, as pointed out in the following extracts.
Visual Inspection of flats
Presence of air vents in the main rooms (living room and bedrooms).
The bottoms of doors have been planed (by 2 cm or 140 cm2 for the kitchen/by 1 cm or 70 cm2 for the bathroom/toilet).
Presence and type of exhaust vents.
Absence of inappropriate air (non airtight doors to the outside, existence of low air vents, etc.)’.
18 – In the light of these texts, the CSC feels that the rules on systems redistributing hot air should be based on the same principles.
19 - Pending the implementation of the necessary texts, the Committee points out that professionals are not freed however of the general safety obligation, which is mandatory even without a legal text. The equipment available on the market must therefore at least meet these general health and safety requirements pending the implementation of adapted and specific legal rules.
20 - Similarly, the rules of the trade relating to installations must be such that they guarantee their correct operation.
C - Solutions proposed pending specific legal rules
21 - Pending the drafting of specific legal rules, the CSC invites professionals to base themselves on close legal rules relative to gas-fired and fuel-fired generators and to controlled mechanical ventilation.
22 – Also, the Committee had already given on 6 January 1993 an opinion on fireplace inserts, which were also sold freely to consumers without them being informed of the serious dangers that can arise from an installation breaching the general safety rules. In the wake of this opinion the public authorities enacted a regulation, the decree no. 93-1185 of 22 October 1993 on consumer safety with respect to fireplace closed hearths and inserts using solid fuels. A similar type of approach should therefore be used since this case showed that a regulatory type decision could be taken rapidly. This decree provides for a specific information procedure for buyers-installers defined in articles 4,5,6 and 7 (see appendix).
23 – The Committee feels however that the mere application by analogy of texts of a legislative character applying to similar equipment does not offer a sufficient safety guarantee, particularly regarding old installations or ones made directly by the user.
24 - Indeed these installations may not have received regular maintenance of all their components and no correct operation guarantee can be given, even if they were built according to the rules of the trade.
25 - Similarly, an installation not designed according to these rules (case of a private individual having done the job himself) may not meet the guarantees laid down. This may be the case for heat generators whose burnt gas exhaust system is disturbed by a ventilation system installed in breach of the rules of the trade: insufficient air vents, interior doors that have not been planed enough, flows of air too high on occasions...
26 - The CSC therefore recommends—for want of a specific legislative framework serving as a basis for certification—the implementation of a technical opinion procedure to characterise, from a ventilation viewpoint, systems redistributing hot air (fan curb, flow and pressure characteristic of the blown air network), and to specify their use conditions (on the basis of the existing ventilation system specifications, the fresh air supply to the house, transit passages and the ‘permeability’ of the house).
27 – Lastly, it should be noted that systems redistributing hot air come within the scope of directive 89/106/EEC on construction products. France's representatives at the European bodies should therefore ask for these systems to be the subject of a mandate given by the Commission to the European Committee for Standardization (CEN) with a view to the drafting of specific legislation.
|The CSC notes that combating deaths and poisoning due to carbon monoxide is a public health priority. And this risk is likely to be exacerbated by the new equipment recently placed on the market—particularly aimed at the general public—such as the kits or discrete components to build systems redistributing hot air.|
The CSC therefore recommends that the government and the bodies concerned should adopt in the shortest possible time the necessary regulations for systems redistributing hot air, by referring to the existing rules. In addition it is necessary to:
Elaborate specific legal rules for systems redistributing hot air, comprising a set of provisions applying to redistribution installations whatever type of fuel and of heating appliance is used. These texts could draw inspiration from the relevant requirements of already existing rules and regulations, particularly the regulation on controlled mechanical ventilation and the directive 90/396/EEC on gas-fired appliances.
Suggest to the European Committee for Standardization (CENT/TC 295—Residential heating and cooking appliance burning solids fuels) that it draft an amendment making it mandatory to specify, in the installation notices for heating appliances, the rules for installing any related systems redistributing hot air.
Suggest to AFNOR (general committee for building legislation) that it draw up an amendment to the document technique unifié (DTU) on the installation of inserts and closed hearths, which amendment would be devoted to the installation of related systems redistributing hot air.
In the meanwhile, and at the same time as the implementation of these measures, the CSC makes the following recommendations:
Systems redistributing hot air should undergo a technical opinion procedure including the lists of adaptable accessories and the written recommendations necessary for correct operation of the whole installation, taking into account in particular the characteristics of the premises and the characteristics of the primary means of heating (the source of the hot air) whatever type of hearth is used by the consumer.
Salesmen and installers should inform consumers of the dangers of carbon monoxide, by any means allowing them to make sure they abide by the precautions to be taken upon installation and during use of this type of equipment, particularly the banned modifications likely to disrupt the operation of the other equipment. Several solutions can be suggested:
1. Upon sale, all systems redistributing hot air, and particularly fans, should be accompanied by a notice pointing out at least
the necessary compliance and correct execution of the fresh air intake for operation of the closed hearth or insert, in accordance with the rules of the trade (D.T.U.)
the measures to be taken for the blown air to return to the generator premises (by planing the bottom of doors for instance).
2. A similar procedure to that used for inserts and closed hearths should be used. When consumers purchase them they are given a document in three parts explaining the installation and safety rules to be complied with. They must, upon signing it, testify they have read these rules, which does not transfer the manufacturer's or installer's responsibility should a malfunction occur.
Lastly, the public authorities should endeavour to ensure that the installation of equipment of this type is reserved for qualified professionals, alone qualified to check the compliance of the whole installation including the heat generator, especially if it is an insert.
The CSC urges consumers to demand:
precise explanations on the risks, compatibility with the rest of the installation, assembly and maintenance of these redistribution system.
a detailed notice accompanying these redistribution systems whether they buy a kit or have the system assembled by a professional.
ADOPTED AT THE SESSION OF 8 NOVEMBER 2000
ON THE BASIS OF THE REPORT BY MR JEAN-PÔL MAMBOURG
assisted by Mr Jean-Michel MAIGNAUD, Committee Technical Adviser, in accordance with article R.224-4 of the Consumption Code
Closed hearth and insert: these systems are defined as follows by article 1 of decree no. 93-1185 of 22 October 1993 on the safety of consumers with respect to fireplace closed hearths and inserts using solid fuels:
"‘Fireplace closed hearth’ means a heating appliance that is intended to be surrounded by masonry. ‘Insert’ means a heating appliance to be inserted in an existing fireplace. Both operate continuously or intermittently, either exclusively on wood, or wood or other solid fuels.’"
Controlled mechanical ventilation: System—generally electric—ensuring the forced renewal of air inhousing.
Discrete: […] 1484; ‘different’; classic Latin: discretus ‘separate’. Maths.: Discrete quantity, composed of separate elements… (Source: Robert).
Discrete components: through an extension of its sense in mathematical language, this term (widely used in electronics and data processing) means components supplied separately and normally intended to be grouped to form a whole (as opposed to integrated components).
D.T.U.: Document Technique Unifié : Document of a legislative character codifying good practices (or rules of the trade) for the use of technical appliances (heat or hot air generators in this instance).
Generator: short for ‘generator appliance’ (which generates, serves to generate). Here it means any appliance transforming any kind of energy into heat (Source: Robert).
kW: kilowatt : unit of power (calorific power in this case) representing 1000 watts.
Ventilation circuit: circuit specially intended for the passage of a gas—air in this instance.