What is a smoking system?
The smoking system is made up of three elements: connection (also called smoking canal) flue and chimney-pot. The connection, as it’s name says, joins the combustion apparatus with the flue and it is an element that must adapts itself to the most different needs; the flue is the vertical part of the system and it represents “the motor” and so an essential part of the smoking system, while the chimney-pot finished the system preserving it from bad weather and winds that can negatively influence the pulling.
It’s functioning is simple, but particularly complex is the pulling estimate necessary for the planner and for the flue technician to assure customers the correct clearance of smoke in the atmosphere.
The cause for which the flue “pulls” is based on the weight difference between smoke and external air. We should notice, in fact, that as the temperature increases the smoke expands and consequently lose weight.
On the estimate’s point of view 80 mathematical passages are necessary against the control of 23 variables connected between themselves to dimension the smoking system to a certain combustion apparatus.
The type of combustible, the potentiality and the type of boiler, and other elements such as its position as regards to the flue are values the determine the difference between two heating systems and for which two different smoking systems are necessary.
For these two characteristics and its function the smoking system is considered as a “thermal machine” that exploiting the remaining energy of the combustion and heating process (smoke temperature) always works and however, on condition that it is regularly maintained and controlled during it’s use. Particular attention must be turned to the system adjustment when the boiler characteristics such as combustible, potentiality and type ( high rendering, condensation functioning etc.) change.
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Is the smoking system indispensable?
Of course! It is an essential element for thermal plants, like for every type of combustion apparatus, and however:
- makes it sure and constant the evacuation of the combustion products from the places where people live;
- corresponds to the real needs of the combustion apparatus, like chemical composition and smoke temperature;
- connected to the contribution of air coming from intake, always remembering that a smoke system starts from the intake;
- reduces to minimum the use of thermal energy suitable for its own working.
The main prerogative is surely the arrival of smoke in the atmosphere preventing any type of discomfort, uneasiness and trouble for close places and overlooked, with particular attention to aspects connected to statics, aesthetics and the functioning of the whole building.
In conclusion to the process of evacuation combustion products, the system must also assure the maximum dilution of smoke with external air, optimize the “plume of smoke” (to make vertical and faster the exit of smoke from the chimney-pot), with the consequent decrease of pollution to “man’s height”.
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When it doesn’t pull anymore:
accidents connected to the unsuccessful working of the smoke systems.
Smoke systems, if abandoned, from useful and efficient they will become dangerous and disadvantageous from the economical and environmental point of view. The statistical studies effected for years by corporations and associations such as CIG (Italian Gas Committee), firemen (with territorial competences) lays emphasis on the responsibility of smoke systems in the most cases of domestic and condominium accidents that involve boilers any kind of combustion apparatus.
Indicative the statistic regarding boilers that work with methane gas, combustible gas that points out a percentage of 87,6% of cases of accidents and intoxications from carbon monoxide due to the unsuccessful working of smoke systems.
Research corporations such as ENEA and CNR have various times discussed the argument “indoor pollution”, in other words air pollution in houses and in condominiums to the detriment of home comfort. Among the cases there are smoke systems that do not work.
As atmospheric pollution concerns, authoritative experts have remembered many times that during the winter period thermal systems, through and by means of smoke systems, contribute to 50% of urban pollution, for which only for a few years towns effect controls and tests of the efficiency of boilers in addition to drastic interventions of blocking car traffic.
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Maintenance:
Rules and obligations beyond conscience and necessity.
Being the owner of goods o using a system involves rights and duties. For respect towards things, people, themselves and others, today as well as in the past negligence for the systems is not admitted.
With the right to live in the building with safety, without excessive economic increases and in full living comfort, the duty of control and the maintenance of systems oppose, the limiting of energetic waste and the polluted emissions in the atmosphere.
For the smoking systems all this is true and is fully verifiable and few examples are needed to understand the importance of the damages caused by a simple maintenance of the flue:
- Rome 1995, Torlonia palace, the flue of a fire place gets on fire because of the spontaneous combustion of smut that wasn’t ever removed from the inside of the smoke system. Some wooden beams increase the fire that was inside the building including the shops beneath. The damages are elevated.
- Rome 1997, Hotel Forum, Four people died during the night because of smoke coming out of a broken flue, on duty in the thermal plant of the hotel.
- Rome 1998, Hotel Excelsior, the smoking system of the central heating goes on fire for excessive depositing of smut that was never removed.
The mortal accidents, those who generate wounds with the destruction of goods and buildings exceed a thousand a year.
The wastefulness of energy varies from 2% to 15% on the total of the combustible used annually. Urban pollution is always greater, like the numbers of days/years in which the proposed authorities order car blocking are increasing.
The rule of reference is clear since it expressly asks and obliges:
- Law 46 of 1990, annual maintenance for thermal systems including the smoke system.
- Law UNI 8346, smoke system maintenance must be done at least once every three years for solid combustion systems, every four years for liquid combustibles and every five years for gas.
- DPR 412 of 1993, in a condominium building every combustion apparatus must have a flue for the transport of the products of roof combustion.
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How to take part to improve the capability of the thermal system?
The phases of intervention are five:
- Internal video inspection preventive of the flue, to assure the possibility of work execution (presence of obstructions, curves, breakages, section changes…);
- System measures;
- Cleaning action;
- Video inspection of control and test of work effected;
- Data control and technical report.
Before beginning the maintenance it is necessary to control the state and general conditions of the system to verify eventual operative difficulties, breakages, and material deteriorating and the following choice of equipment for the intervention. Afterwards the internal and external connection measuring precedes, of the flue and the chimney-pot, with certain attention to the tower, terminal line of the flue going outside of the cover plan.
Cleaning is effected before the opening of the inspection door, closing of connection, disassembly of the chimney-pot, if necessary. The operative systems used are the percussion system working with pulley and rope, and the pole system the allows the cleaning of the flue even from the bottom up.
The internal video inspection control of the system is effected for the research of the causes of an eventual bad operation not visible from the outside.
The smoke technician closes the intervention checking the work effected and registering the data collected during the control of some work tables that allow to check the correspondence to the regulations in force.
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How to restore an old smoke system
In a short while there will be another
intervention field to foresee, the one about
the flues in asbestos that for their function and construction will fall again in the law based on asbestos (Law 27 march 1992, n. 257) that predicts every component in cement – asbestos, the so-called “Eternit”, the census and maintenance plan.
The cancerous danger of asbestos has been assured for years and the laws does not allow the production and commercialing of this material.
The dangerousness of this product is due to the penetration of fibrous particles in lungs that cause tumors to the pleura always with a negative result.
The
restoration of the flues in “Eternit” consists in the capsuling of the pipe with suitable materials, that, in the case of combustible gas they must be waterproof; this procedure allows the use and regular cleaning of the flue with systems described where the covering layer placed results free from abrasions, absolutely waterproof and legal.
Rules:
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Law 10/91, rules for the carrying in effect of the national energetic plan in the matter of the rational use of energy, of energy saving and of the development of renewable sources of energy
(Article 4, c. IV, maximum values of room temperature);
DPR n. 412/93, regulation containing rules for the planning, installation, use and maintenance of the thermal systems of buildings by means of the containing of energy use
(Article 11, c. IV, XII, XIII, XVIII, XIX, XX, use and maintenance of the thermal systems and relative controls).
Law 10 of 1991, in the context of a rationalization of the use of energy, determines the fundamental rules to reach the true energetic saving.
Comma IV of the article 4 is carried into effect from the ministerial decree 412/93, that outlines with abundance of details, the regulation to follow for the reaching of established purposes by the law, specifically in the context of civil heating. In particular towns with over 40,000 residents and for the rest of the territory in the provinces asks to effect with it own employees or external technical groups a control of the occurred maintenance of the thermal system and the state of functioning of the same with a maximum biennial expiration..
Such control activity is accomplished in Europe by chimney-sweeper teachers that assure a regular maintenance and control of the smoke evacuation system.
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Law 46/90, rules for the safety of the systems (Article 1, letter C, application context);
DPR n. 447/91, putting into operation rule of the Law 5 march 1990 n. 46 in matter of security systems
(Article 1, c. V, application context Article 4, letter E, system projecting).
The important novelty introduced by the Law 46 of 1990 is the declaration of conformity that the installer must grant to the owner of the system during the moment of the end of work. This document certifies the execution of the systems perfectly using materials built perfectly.
Currently such law, not subdividing the technical competences relative to the heating system (generator and distribution system) and the smoke system, asks the installers the release of a certificate including all the elements of the system. In the most part of the cases, such document is released incompletely as the part of the system concerning smoke evacuation concerns, not being part of their technical knowledge.
The smoke technician can completely relieve certifying the suitability of the smoke systems. These represent their primary interest where the technical knowledge is based on the control of the flues.
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Decree of the minister of the eenvironment of 12/11/92, general standards for the prevention of atmospheric pollution in the big urban areas and dispositions for the improvement of the quality of the air
(Attachment 4, indications of the measures to adopt in the operative intervention plans
Article 3, civil heating: individualization of the measures to adopt to decrease pollution).
The Minister of the Environment, with the Decree of 12/11/92 has located in civil heating a source of emission of polluting that must be considered the same as the other sources like the automobiles and motorcycles or the industrial and craftsmen activities.
The individualization of the measures to adopt to decrease the pollution produced by civil heating, must consider the indicated precautions in the regional plans of restoration and protection of the quality of the air.
The smoke technician, like it has occurred for years in some European countries, can completely relieve
to such task without further burdening on the national economy
effecting detailed tests to the employee.
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