Internal hydrants are essential elements of fire protection systems that allow flames to be extinguished quickly and effectively in a dangerous situation. Although their use is relatively rare, they are commonly used in certain types of buildings. When do regulations require their installation?
In this article you will learn:
- what regulations govern the use of internal hydrants,
- when the installation of internal hydrants is required,
- what internal hydrants to choose.
Internal hydrants - regulations
The use of internal hydrants is regulated by the provisions contained in the Regulation of the Minister of Internal Affairs and Administration of 7 June 2010 on fire protection of buildings, other construction objects and areas. To understand them, it is also necessary to know the definitions specified in the Regulation of the Minister of Infrastructure of 12 April 2002 on the technical conditions that buildings and their location should meet. It is also worth paying attention to the Polish Standards regarding fixed fire extinguishing devices. They will provide you with information on different categories of buildings and threats. Thanks to them, you will understand which internal hydrants should be used in buildings of a given type.
Internal hydrants – when are they required?
An internal hydrant is a permanent device placed in the water supply network, designed to extinguish group A fires. It has a wider range of operation than a fire extinguisher and is primarily used to stifle a fire in the bud and extinguish burnt-out areas.
The regulations do not require the installation of internal hydrants in every building. Such a necessity occurs only in the case of buildings most exposed to fires. The obligation to use this type of protection therefore applies primarily to structures of specific sizes or functions. These include:
- fire zones classified as human hazard (ZL),
- garages,
- industrial and warehouse facilities,
- high-rise and high-rise buildings.
Each of these cases will require a different type of indoor hydrant. Let's take a closer look at them.
GRAS brand hydrants
Hydrants DN25
DN25 hydrants should be used in fire zones classified as hazardous to people:
- ZL I – discos, cinemas, theatres,
- ZL II – kindergartens, hospitals, social welfare homes,
- ZL V – hotels, boarding houses.
In the above cases, DN25 internal hydrants are required when the fire zone is larger than 200 m 2 . The regulations regarding the ZL III and ZL IV human hazard zones are slightly different, because the obligation to install hydrants depends on the height of the building and the layout of the storeys.
Hydrants DN33
The regulations regarding the use of DN33 hydrants are less complicated. These devices are primarily used to secure garages:
- single-storey – if we are talking about a closed structure intended for more than 10 cars,
- multi-storey – regardless of the number of parking spaces.
Interestingly, DN33 internal hydrants can also be used in some industrial and warehouse premises.
Hydrants DN52
However, DN52 hydrants are mainly used to protect industrial and storage facilities. The obligation to use them results from the density of the fire load in the fire zone and the area of this zone. In order to determine the need to install a hydrant, both of these criteria are combined in various combinations. Some of them also allow the aforementioned use of DN33 type devices.
Hydrant valves 52
Hydrant valves 52 can be considered the fourth type of internal hydrants. They differ from the others in that they do not have a hose. For this reason, they are used on watered risers, maintained at optimal pressure, which is supplied from water supply networks and additionally from fire trucks. The valves are installed in high-rise and high-rise buildings, also to protect fire zones classified as a threat to people ZL IV.
Rules for the installation of internal hydrants
The internal hydrant consists of a valve, hose, nozzle, and sometimes a drum or reel. The individual types of devices (DN25, DN33, DN52) differ primarily in the diameter of the hose. This has a direct impact on their construction and the shape of the cabinets in which they are placed.
The condition for installing an internal hydrant of a given type is to guarantee the minimum water collection capacity from the installation. In the case of this device, it is measured at the nozzle outlet. This parameter depends on the type of hydrant and its application:
- 1 dm 3 /s - for internal hydrants DN25,
- 1.5 dm 3 /s - for internal hydrants DN33,
- 2.5 dm 3 /s - for internal hydrants DN52 and valves DN52
When installing fire hydrants in a building, it should be remembered that their range should cover the entire surface of the building. The devices must therefore be located on each floor – especially at entrances, in corridors or evacuation exits from rooms at risk of explosion. Another important issue is to provide enough space to allow for the efficient and safe unwinding of the hose.
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GRAS internal hydrants in the Onninen offer
When looking for high-quality internal hydrants for the needs of fire protection installations, be sure to check out our online wholesale offer! Here you will find reliable GRAS brand devices in many variants adapted to the specific requirements of the customer.
Among the models available in our assortment, there is no shortage of universal DN25 hydrants, nor efficient DN52 hydrants. There are also various types of accessories that allow you to create a functional and aesthetically camouflaged fire protection system in any facility.
Internal hydrants DN25 from the GRAS range are equipped with a patent lock and a semi-rigid hose in a 20- and 30-meter version. Thanks to the modular design of the product, its flexible configuration is possible, in accordance with individual needs. This is a device that should not be missing in schools, kindergartens, office buildings, hotels, cinemas or shopping malls.
DN52 hydrants available in the GRAS offer are equipped with a flat hose and double-sided power supply. Devices of this type - like DN25 variants - are suitable for surface mounting. Their cabinets are covered with polyester powder paint, thanks to which they are perfect for industrial use.
By choosing GRAS products, you gain a guarantee of the highest quality of workmanship and operational reliability. This is a Polish brand present on the market since 1985. It specializes in designing, manufacturing and distributing fire protection solutions and equipment used in rescue and occupational health and safety. If you want to create an excellent security system, trust an experienced manufacturer such as GRAS, whose products can be found in the offer of the Onninen.pl hydraulic wholesaler .
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