Fire protection and smoke exhaust systems

fire protection system

Types of fire protection system

Based on the extinguishing medium used, fire protection systems can be divided into:

water-based fire suppression systems (sprinkler and drencher systems), the operation of such systems is based on spraying water directly over the fire; the advantage of this system is its high efficiency in facilities where there is a risk of rapid fire spread or where cooling of the facility is required;
water mist fire suppression systems, these systems utilise water mist technology to break up water droplets into particles of less than 50 µm in diameter. At high temperatures, these particles rapidly evaporate. This process has the simultaneous effect of cooling the extinguished objects and displacing oxygen in the vicinity of the fire source. The advantages of these systems lie in the fact that they use smaller water jets than water-based systems and that the effects of water extinguishing such as flooding can be reduced.
foam fire suppression systems, these work by cutting off the fire source from the oxygen supply by covering or filling the burning object with foam. Foam systems are most often built in a similar way to water systems - a foaming concentrate is added to the water at a certain section of the system, then the mixture is aerated. Foam systems usually use nozzles, ejectors, foam chambers, water-foam monitors or foam outlets at the end of the distribution system. The advantages of this system include isolating the fire from the combustible material, cutting off the oxygen supply and not flooding the extinguished objects.
gas fire suppression systems, the action of these systems is to displace oxygen from the extinguished space and/or interrupt the chemical combustion reaction. Using gas is the safest way to extinguish a fire involving electronic equipment. A huge advantage of gaseous extinguishing media is that they do not conduct electricity.
powder fire suppression systems - the operation of these systems consists of using the anti-catalytic effect of the extinguishing powder. This stops the combustion process and extinguishes the fire. These are the least popular systems. They are used when the use of other fire extinguishing systems is not possible or their installation is not cost-effective. The advantages of this system reside in the fact that it works effectively in sub-zero temperatures and is not harmful to the environment.

Fire suppression equipment can be subdivided according to the type of surface to be extinguished. Water, foam or mist systems are most commonly used in large volume facilities, while for facilities up to approx. 1000 m³ - gas systems are used. In smaller facilities, drencher systems or water mist fire suppression systems can be used.

Gas extinguishing systems or dedicated solutions, such as (Active Automatic Fire Extinguishing Line), can be used to extinguish fires arising during machinery and electrical equipment operation.

Passive fire protection

Another method of fire prevention is passive fire protection. It involves slowing or stopping the spread of fire through the use of appropriate materials and equipment consistent with the design of the facilities and the application of fire prevention procedures. The basic elements of passive fire protection are the Fire Detection and Fire Alarm Systems (SSP), which consist of the Fire Alarm System (SAP) and the Voice Alarm System (DSO).

The SAP system makes it possible to detect fire at an early stage of its development and to transmit information about the fire to a control panel that informs the relevant persons or institutions of the danger.

The DSO system is used to broadcast sound signals: warning signals and voice announcements, automatically broadcast when a signal is received from the Fire Detection and Fire Alarm System (SSP).

Smoke extraction systems

smoke exhaust systems

Smoke extraction (SO) systems are designed to extract fire gases (smoke) from the premises and replace them with a stream of fresh air to compensate for the pressure difference created during a fire and to ensure that survivors can breathe. Smoke exhaust systems can be divided into the following:

gravitational systems,
mechanical systems,
mixed systems,
overpressure systems.

Gravitational smoke extraction refers to a system that primarily uses the phenomenon of convection, i.e. the rising of hot smoke.

Mechanical smoke exhaust systems are systems that use various types of mechanical equipment (fans, jets) to pump fire gases. Mechanical devices may be either part of a smoke exhaust system or individual smoke exhaust points.

Mixed (hybrid) smoke exhaust systems are solutions that combine the functionality of smoke exhaust and smoke prevention systems.

Overpressure smoke exhaust systems - the main purpose of this system is to prevent the smoke from filling the room. The basic principle of this system is to establish the direction of air flow (pressure gradient) - the highest pressure is maintained on escape routes.

Another division of smoke extraction systems is between ducted smoke extraction(a system providing vertical smoke extraction as a result of the use of an exhaust duct system) and ductless smoke extraction (a system involving the horizontal movement of air together with the smoke, jet ventilation).

Where should fire protection systems be used?

Fire protection systems must be used preferably in all facilities where people are present and where the products of their labour are stored. Consideration should be given to the facilities listed in the Decree of the Minister of Internal Affairs and Administration of 7 June 2010 on the fire protection of buildings as well as other structures and areas [5].

commercial and exhibition buildings;
theatres with over 300 seats;
cinemas with over 600 seats;
catering buildings with over 300 seats;
sports and performance halls with over 1,500 seats;
hospitals and sanatoriums with over 200 beds;
psychiatric hospitals with over 100 beds;
residential care homes and rehabilitation centres for the disabled with over 100 beds;
workplaces employing more than 100 people with disabilities;
tall public-use facilities;
collective residential buildings with over 200 beds;
National Archives;
museums and monuments under the care of the General Conservator of Monuments in agreement with the Chief Fire Officer of the State Fire Service;
server rooms, data processing centres;
telephone exchanges;
underground garages where the fire zone is more than 1500 m² or those with more than one underground storey;
metro and underground railway stations;
stations holding over 500 people at any given time;
banks where the fire zone includes a front desk and covers an area of more than 500 m²;
libraries with old prints, archives.

Fire ventilation system - components

A traditional ducted fire ventilation system consists of the following components:

Ventilation ducts,
Ventilation grilles,
Exhaust fans,
Fire dampers.

Special attention should be paid to escape routes. Among the most common are staircases and garages.

Fumes and fire gases make it impossible to evacuate people from buildings due to flue gas poisoning. This applies to both garages and staircases (escape and rescue routes). Fire ventilation regulates the flow of air and fumes in such a way as to draw the fumes and gases to the outside as quickly as possible and facilitate evacuation.

Fire ventilation systems, with regard to the objective to be achieved, taking into account the type of equipment, can be divided as follows [1]:

SHEVS (Smoke and Heat Exhaust Ventilation System) system to ensure that smoke is removed from the layer accumulated under the ceiling and that a smoke-free space is maintained so that people can evacuate,
Smoke and heat control system - a system designed to keep smoke in a designated area between the source of the fire and the area where it is to be removed, so that emergency crews have easy access to the source of the fire,
Smoke Clearence, dilute - a system that is designed to remove smoke and dilute it with the incoming compensating air to reduce its temperature and toxicity.

Division of fire ventilation systems

ventilation systems

Fig. 1. Flow chart of the division of fire ventilation systems according to the type and kind of equipment used,
highlighting the most commonly used systems in enclosed garages [1,2].

garage fire ventilation

Fig. 2. Division of garage fire protection installations

Human life and health depend on the correct operation of fire ventilation situated on escape routes.

To ensure that the duct system (fig. 3) works properly, the garage must be divided into smoke zones using smoke curtains (mark 1). Their function is to stop the smoke from spreading to the rest of the garage. The smoke generated by the fire is removed through grilles located on the ventilation ducts (mark 2). There is a clear division between the hot smoke layer that persists under the ceiling and the smoke-free layer (mark 3). The compensation air is supplied in such a way that it does not cause smoke to descend (mark 4).
fire protection ventilation system

Fig. 3. Principles of operation of a ducted smoke and heat exhaust ventilation system [3].

Fig. 4. Operation of the ducted ventilation system under normal conditions [2,4].

Fig. 5. Operation of the ducted ventilation system during a fire [2,4].

Exhaust grilles located at two heights above the floor level (Figures 4, 5):

At a height of more than 1.8 m- removing lighter fractions of contaminants,
At a height of less than 0.8 m above floor level - removing contaminants heavier than air.

During normal operation, approximately 60% of the air is removed from the ceiling space, with the remaining 40% removed from floor level. During a fire outbreak, the bottom exhaust is cut off and 100% of the fire airflow should be extracted through the top grilles.

[1] Węgrzyński W., Krajewski G., Sulik P., Systemy wentylacji pożarowej w budynkach, Inżynier Budownictwa, 2014 (9)
[2] Jelińska – Wenta S., Analiza dwóch systemów oddymiania i wentylacji w garażach wielostanowiskowych, praca dyplomowa magisterska 2017 pod kierunkiem K. Gładyszewskiej-Fiedoruk
[3] Węgrzyński W., Krajewski G., Systemy wentylacji pożarowej garaży. Projektowanie, ocena, odbiór. ITB, Warszawa 2015
[4] Mizieliński B., Kubicki G., Wentylacja pożarowa oddymianie: Wydawnictwa WNT Warszawa 2012
[5] Regulation of the Minister of Interior and Administration Regulation of 7 June 2010 on the fire protection of buildings as well as other structures and areas (Dz.U. /Journal of Laws/ of 2010 no. 109, item 719)

Smoke extraction of buildings in view of legislation

Main requirements concerning smoke ventilation systems and equipment
Requirements for the smoke extraction system [1]:

The smoke and heat exhaust ventilation system shall remove smoke at an intensity that ensures that in the time required to evacuate people in protected passageways and escape routes, there is no smoke or temperature that prevents safe evacuation.

A constant supply of outside air should be provided to an enclosed garage to make up for the loss of air discharged with the smoke.

Art. 245 points 1 and 2 of the Regulation of the Minister of Infrastructure [2] recommends that "staircases in medium-high public buildings (ZL I, II and III) and collective residence building (ZL V), as well as in low ZL II buildings and some industrial buildings, should be enclosed and shut with doors and equipped with smoke prevention or smoke removal equipment".

Pursuant to Art. 256 section 2 of the Act [2], such equipment should also be used in staircases (enclosed and shut with doors with a fire resistance class of at least EI 30), the entrances to which are to serve as the end of exit access.

This is also applicable to multifamily residentials (ZL IV). Where a staircase does not meet the above-mentioned conditions, the length of exit access running along the flights and landings of the staircase shall be included in the length of the escape route. This may result in exceeding the permissible exit access length, which, in the case of a single direction of evacuation, amounts to:

10 m in fire zones ZL I, II and V,
30 m (including 20 m on a horizontal escape route) in ZL III,
60 m (including 20 m on a horizontal escape route) in ZL IV,

whereas in the case of 2 exit accesses:

40 m in fire zones ZL I, II and V,
60 m in ZL III, - 100 m in ZL IV.

The specified exit access lengths are increased by 50% when the escape route is equipped with smoke exhaust devices activated automatically by the smoke detection system.

The fire requirements for garages are outlined in chapter 8 of the Regulation [2]. If a garage does not offer a direct entrance or exit from the building (including car lifts) or if it is larger than 1,500 m2 , the installation of a fire alarm system activated by a smoke detection system is required. Thus:

Art. 277. Garage fire area [1]

1. The area of a fire zone in an above-ground or underground enclosed garage shall not exceed 5000 m².

2 The area (...), may be increased by 100 % if one of the following conditions is fulfilled:

1) protection of the fire area with fixed automatic water extinguishing equipment is provided;

2) walls, separating no more than two parking spaces each, have been constructed with a fire resistance class, in the solid part at least E I 30, from the floor to a level that ensures a ceiling clearance of 0.1 to 0.5 m along their entire length.

3. Fixed automatic water extinguishing systems shall be used in an enclosed garage comprising more than two underground storeys or located below the second underground storey. The requirement does not apply to a garage fire zone that has a direct entrance or exit from the building.

4. A smoke and heat exhaust ventilation system activated by a smoke detection system shall be used in the fire area of an enclosed garage where this area has no direct entrance or exit from the building or where the area exceeds 1500 midx2.

5. If the solution referred to in section 2 point 1 is used, the fire resistance class of the smoke and heat exhaust ventilation system ducts must comply with the requirements specified in Art. 270 section 2 only regarding the fire tightness criterion (E).

Art. 278 Emergency exits from a parking garage [1].

1. At least two emergency exits shall be provided from a parking garage fire zone which has more than 25 parking spaces and is not equipped with a smoke and heat exhaust ventilation system or has an area exceeding 1500 midx2; one of these emergency exits may be either an entryway or an exit.

2. In the case of a parking garage fire zone comprising more than two storeys, emergency exits shall be provided at each storey level. The length of the walkway from the parking position to the nearest emergency exit must not exceed:

1) in an enclosed parking garage - 40 m;

2) in an open parking garage - 60 m.

3. The length of the walkway referred to in section 2 point 1 may be increased in accordance with the rules specified in Art. 237 sec. 6 and 7. Art. 237 sec. 6 point 2 does not apply if a jet fan smoke and heat exhaust ventilation system is used.

4 The emergency exit should also be accessible if the parking garage entryway or exit or the gate between fire zones is closed.

5. If the parking level is no more than 3 m above the level of the ground next to the building, an unenclosed external staircase may serve as an emergency exit.

6. In an underground garage, fire zones with a surface area of more than 1500 midx2 shall, in the event of fire, be capable of being separated from each other and from the above-ground storey of the building by means of doors, gates or other closures with a fire resistance class of not less than E I 30.

Art. 15 Evacuation requirements [3].

1. Appropriate evacuation conditions shall be provided from every place in the building intended for human occupancy to ensure rapid and safe evacuation from the danger or fire zone, adapted to the number and state of fitness of the occupants and the function, construction and dimensions of the building, and the use of technical fire safety measures consisting of:

1) the provision of a sufficient number, height and width of emergency exits;

2) maintaining the permissible length, height and width of passageways and escape routes;

3) the provision of a fire-safe enclosure and the separation of escape routes and rooms;

4) securing the escape routes listed in the technical and building regulations against smoke, including the use of smoke prevention devices or devices and other technical and construction solutions ensuring the removal of smoke;

5) the provision of emergency lighting (evacuation and backup lighting) in the rooms and on the escape routes listed in the technical and building regulations;

6) ensuring that warning signals and voice messages can be sounded by the voice alarm system in buildings where it is required.

2. Appropriate evacuation conditions are specified in the technical and building regulations.

At least two emergency exits shall be provided from a parking garage area which has more than 25 parking spaces and is not equipped with a smoke and heat exhaust ventilation system or has an area exceeding 1,500 m². In the case of a parking garage fire zone comprising more than two storeys, emergency exits shall be provided at each storey level. Emergency exits from each parking garage zone are to be available not only when the gates between the zones are closed, but also when the entrance or exit from the garage is closed.

[1] Regulation of the Minister of Infrastructure on the technical conditions to be met by buildings and their location of 12 April 2002. (Dz.U. /Journal of Laws/ no. 75, item 690 as amended)
[2] Regulation of the Minister of Infrastructure on the technical conditions to be met by buildings and their location of 17 November 2017. (Dz.U. /Journal of Laws/ 2017 item 2285)
[3] S. Jelińska – Wenta. Analiza dwóch systemów oddymiania i wentylacji w garażach wielostanowiskowych, praca dyplomowa magisterska 2017 pod kierunkiem K. Gładyszewskiej-Fiedoruk

How to design a fire protection system? What should be kept in mind?

The design of fire protection systems should be carried out in parallel with the design of the building together with other internal systems.

The fire alarm system should be equipped with appropriate signalling equipment to indicate a fire risk in the building. It should be tailored to the type of the building. There should be at least one fire alarm in each part of the building. The location of the server room in the building is also very important.

A fire protection system consists of:

detectors connected to alarm devices,
the division of the building into fire zones,
determining how to supervise the fire protection system, displaying its indications.

Many public buildings and multifamily residential buildings use smoke extraction systems. They act as a complement to fire protection systems or are a component of them.

The smoke extraction system consists of:

a control panel with independent power supply,
smoke detectors,
smoke dampers,
appropriate fire- and temperature-resistant wiring,
air supply.

Types of alarm devices in fire protection systems
The choice of fire alarm device depends on many factors, including the environment in which it is expected to operate. Therefore, alarm devices are divided into:

internal,
external.

Depending on the way in which information about a fire is signalled, alarm devices are divided into:

vocal,
optical,
acoustic,
mixed.

In addition, alarm devices in fire protection systems can be:

conventional,
addressable.

Fire protection installations should be designed so as not to impede evacuation.

Requirements for smoke and heat exhaust ventilation system ducts, with regard to fire and smoke tightness criteria:

Ducts operating in a single fire zone shall have a fire resistance class - E600S, at least the same as the fire resistance class of the ceiling. The use of a lower smoke class E300 S is permitted, only on condition that the design smoke temperature does not exceed 300 ⁰C.
Ducts operating in more than one fire zone shall have a fire resistance class EIS at least as high as the fire resistance class of the ceiling.

smoke exhaust system
Requirements for shut-off dampers in smoke and heat exhaust ventilation system ducts, with regard to fire and smoke tightness criteria:

Shut-off fire dampers operating in a single fire zone shall be automatically actuated and have at least the same fire resistance class - E600S AA - as the ceiling damper. The use of a lower smoke class E300 S is permitted only on the condition that the design smoke temperature generated during a fire does not exceed 300 ⁰C,
Shut-off fire dampers operating in more than one fire zone shall have a fire resistance class EIS AA at least as high as the fire resistance class of the ceiling.

Requirements for smoke exhaust fans:

Class F600 60 smoke exhaust fans - if the predicted smoke temperature exceeds 400 ⁰C,
F400 120 class smoke exhaust fans - in other cases, if a calculation analysis of the smoke temperature and ensuring the safety of the emergency crews indicates this is a possibility.

Requirements for smoke dampers in gravity smoke and heat exhaust ventilation system:

Class B300 30 - for automatic dampers,
Class B600 30 - for dampers that can only be opened manually [1].

All of the above smoke extraction system components should comply with EN 1351 - 4:2008 Fire classification of construction products and building elements. Part 4: Classification using data from fire resistance tests on components of smoke control systems [2].

The control of fire dampers can take place:

automatically (the damper is held in the waiting position, a rise in temperature causes it to close),
remotely (the damper operates under the influence of an external signal).

[1] Regulation of the Minister of Infrastructure on the technical conditions to be met by buildings and their location of 12 April 2002. (Dz.U. /Journal of Laws/ no. 75, item 690 as amended)
[2] S. Jelińska – Wenta. Analiza dwóch systemów oddymiania i wentylacji w garażach wielostanowiskowych, praca dyplomowa magisterska 2017 pod kierunkiem K. Gładyszewskiej-Fiedoruk

How to choose correct fitter for fire protection systems?

A fire protection installation is subject to the same rules as any other internal installation, i.e. the design is done first, then the installation. An experienced fitter can spot design errors, the most common of which include:

incorrectly setting the sound level when selecting the alarm devices
not synchronising alarm elements (audible and visual) operating in the same room,
selecting category A (indoor) alarm devices for outdoor use based solely on the extent of protection against access and against external IP factors (International Protection Rating or Ingress Protection Rating),
alarm devices should cover the entire room,
lack of optical signalling in rooms where acoustic signalling is inadequate.

Even a correctly designed fire protection system will not function adequately if proper attention is not paid during installation:

fire alarm devices, both optical and audible, should be mounted via an installation box or using short circuit isolators,
non-combustible wires must be used (when connecting the control panel to the first alarm device and in the connections between the boxes),
the installation boxes must be mounted to structural elements with adequate fire resistance,
the alarm device must be mounted in a prominent position,
to connecting equipment to a non-dedicated type of current or using an inappropriate current,
to the unsuitability of the wiring for components supplied with different voltages.

In order to avoid the above mistakes, the installer (fitter) of fire protection systems must be someone experienced in the execution of fire protection installations and safeguards. The regulations (legal requirements) in Poland do not specify specific requirements to be met by a fitter. It is advisable for the installer to train for the installation and commissioning of the various fire protection systems.

Courses or training courses which end in an examination and issue certificates or certifications that one is an authorised installer of a particular system are a professional perk indicating that the installer deals responsibly with fire protection systems. Courses and training in installation and commissioning are provided by distributors and manufacturers of fire protection systems. It is advantageous if the fitter has either an electrical (energy) authorisation or/and a telecommunications authorisation.

Use of fire dampers

Shut-off dampers in ventilation and air-conditioning systems are an important component of fire protection systems in buildings. This applies to all types of buildings (public buildings, residential buildings, production and storage halls, etc.) as well as sites such as tunnels, subways, stations, underground passageways, etc.

Shut-off dampers restrict the spread of smoke, fire and the associated hot air. During a fire, human deaths most often occur as a result of smoke poisoning. Smoke also disorientates people, making it difficult to evacuate the facility.

The principle of operation of all fire dampers is the same - during standard operation, the fire damper is open. During a fire, the damper closes, cutting off the airflow.

Types of fire dampers Considering the damper drive:

dampers with electromagnetic trigger control mechanism,
dampers with thermal fuse (or ampoule),
dampers with electric drive.

Considering the shape of the damper:

rectangular fire dampers, with a single-plane cut-off partition
multi-blade dampers,
round dampers.

Fire ventilation shut-off dampers (smoke exhaust dampers) represent a separate type of dampers. These are different from the shut-off fire dampers. The fire ventilation shut-off damper is a component of the smoke and heat exhaust ventilation system of a building; it extracts smoke to the outside of the building, while the shut-off fire damper is a component of the fire protection system, the purpose of which is to prevent the spread of smoke.

Smoke exhaust dampers are installed in building elements (wall, ceiling, etc.). Their principle of operation is the opposite of that of fire dampers. The damper is closed under standard conditions and opens when smoke is present [1].

According to the Regulation of the Minister of Infrastructure of 12 April 2002 on the technical conditions to be met by buildings and their location imposes an obligation to use them in forced ventilation and air-conditioning systems in buildings other than single-family dwellings and those dedicated to individual recreation "Art. 268:

4. At the point of passage through fire separation elements, ventilation and air-conditioning ducts shall be fitted with fire dampers of a fire resistance class equal to the fire resistance class of the fire separation element in respect of fire tightness, fire insulation and smoke tightness (E I S), subject to sec. 5.

5. Stand-alone or enclosed ventilation and air-conditioning ducts routed through a fire zone in which they do not operate shall have the class of fire resistance required for the fire separation elements of those fire zones for fire tightness, fire insulation and smoke tightness (E I S) or shall be fitted with fire dampers in accordance with section 4.

6. In fire zones where a signalling and alarm system is required, fire dampers shall be actuated by this system, irrespective of the thermal fuse used" [2].

Meanwhile, in accordance with Regulation [2], Art. 270 specifies the requirements for a smoke and heat exhaust ventilation system:

3. Shut-off dampers for smoke and heat exhaust ventilation system ducts, operating in:

1) a single fire zone shall be automatically actuated and have a fire resistance class for fire tightness and smoke tightness - E600 S AA, at least as high as the fire resistance class of the ceiling as defined in Art. 216, however, it is permitted to use class E300 S AA if the resulting smoke temperature during a fire does not exceed 300°C,

2) more than one fire zone shall be automatically actuated and have a fire resistance class E I S AA at least as high as the fire resistance class of the ceiling as defined in Art. 216.

The selection of fire dampers is made according to the type of building. The fire protection system of the building should be uniform (made by a single manufacturer). The selection should take into account:

fire tightness, i.e. the damper's ability to prevent the passage of flames and hot gases, and the damper's resistance to heat-related deformation,
fire insulation, i.e. limiting the temperature rise of the damper surface on the fire-free side,
smoke tightness, i.e. the ability of the damper to prevent the passage of smoke.

The shut-off dampers should be installed in building partitions with the same fire resistance class. In special cases, they can be installed in partitions with a lower fire resistance class, but the smoke tightness criterion must still be maintained..

[1] EN 1366-2:2015-08 Fire resistance tests for service installations - Part 2: Fire dampers
[2] The Regulation of the Minister of Infrastructure of 12 April 2002 on the technical conditions to be met by buildings and their location imposes an obligation to use them in forced ventilation and air-conditioning systems in buildings other than single-family dwellings and those dedicated to individual recreation.

Fire valves - what to look for when buying them?

Fire shut-off valves are installed at the ends of a general (comfort) ventilation system and at the points where the ventilation system passes through building partitions. These valves separate the fire zones from the rest of the building.
Depending on the direction of air flow, a distinction can be made between supply and exhaust valves.

Advantages of fire shut-off valves:

fire resistance (usually up to EIS 180),
possibility of using valves with a solenoid trigger,
installation in ceilings and walls,
can be installed ductless.

For example, a fire valve installed in a partition wall with a ventilation duct attached on one side has a fire tightness, insulation and smoke tightness of not less than 180 min.
Fire valves are most commonly found in sizes DN 100, DN 125, DN 160 and DN 200.

It is worth emphasising that fire valves are components of a fire safety system, so compliance with the relevant statutory provisions is essential.

The main task of the valves is to regulate the air flow. Fire valves are installed to prevent any change in its position. Such changes could be caused by an increase in the temperature of the air being transported and thus a change in the dimensions of the valve components.

Most fire valve companies take 72°C as the limiting temperature. Thus, when the temperature of the air flowing through the valve exceeds 72°C, the fusible link insert causes the valve spring to release and consequently the valve (fire shut-off valve) to close tightly.

Valve seals (thermosetting) are usually made from polyurethane. Fire valve mountings are made of galvanised steel or materials with similar properties.

A modern design combines a ventilation valve and a shut-off fire damper. The advantages of such designs are:

higher fire resistance,
reduced dimensions,
greater possibilities of configuration and application.

The main component of the design is the shut-off fire damper. It comes in the following sizes (similar to fire valves): 100, 125, 160, 200 mm. Its design ensures low air flow resistance. It is possible to equip the damper with one or two limit switches to signal the current position of the shut-off partition.

How to select the right ducts and fittings?

The purpose of smoke and heat exhaust ventilation systems is to remove hot gases and smoke from the fire area, creating smoke-free zones. This ensures that firefighting operations and the evacuation of people are possible. The smoke ducts are basic components of a smoke and heat exhaust ventilation system.

Smoke extraction ducts - functions

They are used to transport air (as ventilation ducts),
They are used to extract smoke from the fire zone.

Art. 270 of the Regulation [1] sets out the requirements for a smoke and heat exhaust ventilation system:

1. A smoke and heat exhaust ventilation system should:

1) remove smoke at an intensity that ensures that in the time required to evacuate people in protected passageways and escape routes, there is no smoke or temperature that prevents safe evacuation,

2) have a continuous supply of outside air to make up for the shortfall of that air as a result of its discharge with smoke (...).

2. Smoke exhaust ducts operating in:

1) a single fire zone shall have a fire resistance class for fire tightness and smoke tightness - E600 S, at least as high as the fire resistance class of the ceiling as defined in Art. 216, however, it is permitted to use class E300 S if the resulting smoke temperature during a fire does not exceed 300°C,

2) more than one fire zone shall have a fire resistance class EIS at least as high as the fire resistance class of the ceiling as defined in Art, 216 (...)

The smoke and heat exhaust ventilation system should be made of appropriately classified materials and components. Smoke ducts are most often made from steel sheets with rectangular and circular cross-sections. When exposed to high temperatures, the steel sheet expands (at approximately 600°C by 0.7-0.9 mm per 1 m), causing the ducts to lose their tightness and fire and smoke to spread.

Therefore, suitable components are added to the steel, and expansion joints and flexible inserts are used in the smoke and heat exhaust ventilation system. The role of the expansion joints can be taken over by suitably shaped ductwork. Their main purpose is to compensate for the length of ducting caused by the high temperatures arising during a fire.

The duct connection is also important and should be executed using heat-resistant materials. Ventilation ducts made of fire-resistant gypsum board, mineral wool boards or mats, fibreglass, vermiculite, silicate-cement and silicate boards are less commonly used.

Duct silencers are a component of ventilation systems. They can be part of a comfort ventilation system that also acts as a smoke and heat exhaust ventilation system. In this case, the sound-absorbing material is very important as it must be able to withstand high temperatures. The most commonly used material is the same as for the ducting of the smoke and heat exhaust ventilation system. At present, silencers for smoke and heat exhaust ventilation system which also act as flexible duct connectors are produced.

[1] The Regulation of the Minister of Infrastructure of 12 April 2002 on the technical conditions to be met by buildings and their location imposes an obligation to use them in forced ventilation and air-conditioning systems in buildings other than single-family dwellings and those dedicated to individual recreation.

How to maintain fire protection systems?

In order to maximise the fire safety of buildings, fire protection systems must be systematically inspected and maintained. Every building administrator is obliged to maintain fire protection systems. This is regulated by law [1]. Maintenance of fire protection systems should take place as often as indicated by the manufacturers of these systems, with a minimum of once a year [1]. Once every five years, internal hydrant components should be maintained.

There are other reasons apart from regulation as to why a system review needs to be carried out. Among the most common are:

malfunctions,
hidden defects,
improper installation,
external/atmospheric factors,
mechanical damage.

Inspection and maintenance of fire protection systems must only be carried out by persons properly trained in this field. Professionals should have the skills and authorisations required to inspect, maintain and possibly repair the fire system in question. If a person does not have the appropriate skills and authorisations, they cannot maintain or repair fire protection systems.

CEN/TS 54-14:2004 [2] describes guidelines for the planning, design, installation, acceptance, operation and maintenance of fire alarm systems. This document refers to systems designed to protect life and protect property. CEN/TS 54-14:2004 addresses installation issues with one or more call points. Point 4.8 [2] states "Natural or legal persons performing any work that is the subject of these guidelines should be competent, experienced and qualified". Point 7.7 (concerning installation of the system) and point 8.6 (concerning commissioning of the system) state that these activities should be carried out by persons with adequate theoretical and practical knowledge and appropriate qualifications. Only point 11.8 (on maintenance) states that maintenance calls for trained professionals.

Technical inspections of smoke extraction systems are carried out in accordance with [1], [3] and the manufacturer's technical and operating documentation. Most manufacturers require inspection of the electric and pneumatic smoke extraction system twice a year, every 6 months. In cases where the manufacturer recommends inspections more often than once a year, as stated in the regulation [1], these should be carried out at the frequency indicated by the manufacturer.

[1] Regulation of the Minister of Interior and Administration Regulation of 7 June 2010 on the fire protection of buildings as well as other structures and areas (Dz.U. /Journal of Laws/ no. 109, item 719)
[2] PKN-CEN/TS 54-14:2020-09 - Fire detection and fire alarm systems - Part 14: Guidelines for planning, design, installation, commissioning, use and maintenance
[3] PN-B-02877-4:2001/Az1:2006 - Fire protection of buildings - Gravity systems for smoke and heat extraction - Design principles

The article was written for the company Alnor Systemy Wentylacji Sp. z o.o. by dr hab. inż. Katarzyna Gładyszewska-Fiedoruk.

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