Fire extinguishing requirement measurement DVGW W 405

Löschwasser Prüfung DVGW worksheet W 405 of February 2008 deals with the determination of extinguishing water quantities in the event that extinguishing water is obtained through the public drinking water supply pipe network. The Water Information No. 99 lists additional requirements on the part of the fire brigades and possible restrictions. With our technology and our trained staff, we are able to check and log the performance of your extinguishing water supply. With little effort and without interrupting the water supply, we determine the extinguishing water flow of your hydrants. This can be done for both municipal facilities and commercial extinguishing water devices.

The adequate supply of extinguishing water has become a more and more noticed topic within the utility industry and especially during the approval phase of the construction project. A distinction must be made here between the basic supply to be provided by the drinking water supplier and the extinguishing water requirement. For the fire brigade, the public supply is often the source of extinguishing water. When drawing from drinking water networks, avoid dropping the pressure in the pipe network too far. It should also not lead to a change in the flow conditions or create impurities through backflow

In the past, people were more often willing to choose a larger pipe diameter in favor of the extinguishing water supply. In the meantime, due to the risk of subsections that are no longer penetrated, a closer look at the dimensions is required. Added to this is the lower consumption of water by end customers, which increases this problem.

The municipalities ensure the basic supply of fire water. The extinguishing water requirement is determined for the respective extinguishing area depending on the structural use and the risk of fire spreading. The property-related fire protection that goes beyond the basic protection is referred to as "property protection".

Extinguishing water requirement for property protection

Löschwasser Prüfung The demand for extinguishing water for the protection of property is defined as the demand for extinguishing water that exceeds the basic supply for fire fighting.

As part of a building permit procedure, the municipality has to check the extinguishing water supply for the property to be approved and confirm the sufficient supply to the district.

In addition to the opinion on the general development, a special confirmation note on the extinguishing water supply is included in the opinion on the building application.

If there is an increased risk of fire as a result of structures or other uses of a property, or if this would pose a risk to the life or health of a large number of people or a particular environmental hazard in the event of a fire, explosion or other damaging event, A need for extinguishing water that goes beyond the basic supply may be necessary for property protection

The actual demand has to be determined by expert planners and evaluated within the framework of the building permit procedure. If no regulation has been made in the building permit procedure, the local authority may oblige the person responsible for building law to keep the necessary fire-fighting water supply available which goes beyond the basic supply.

Basic supply with extinguishing water

The basic supply of extinguishing water depends on the structural use and the risk of fire spreading in a protected area / construction area. According to Section 17 of the Building Utilization Ordinance, building areas are classified and the technical rule DVGW worksheet W 405 specifies the guideline values for the required extinguishing water requirement of the respective class based on the risk of fire spreading. The basic supply can be ensured from the public drinking water pipe network and / or through other measures.

For the basic supply, only extinguishing water extraction points (hydrants) may be used that deliver at least 24 m3 / h (400 l / min) of extinguishing water over a period of two hours and are within a radius (radius) of 300 m (extinguishing area) around the fire object . Proof of the actual performance and further information on the drinking water pipeline network must be provided by the local water supplier on request.

If the drinking water pipe network is not sufficient to cover the entire fire-fighting water requirement and there are no inexhaustible water sources available, the responsible municipality has the following cover options:

  • Extraction from extinguishing water ponds acc. DIN 14210

  • Extraction from extinguishing water wells according to DIN 14220

  • Withdrawal from extinguishing water tanks acc. DIN 14230

  • Extraction from an independent extinguishing water network

Extinguishing water withdrawal points

Extinguishing water withdrawal points are devices and processes for providing water for fire protection. Cities and municipalities must ensure an adequate supply of extinguishing water for the fire brigades in order to guarantee fire protection. This is generally done in the form of a central extinguishing water supply, in which the water distribution system of the drinking water supply is supplemented by extraction points for extinguishing water, the hydrants. Where this is not possible to a sufficient extent, water extraction points are provided from streams, lakes or specially created extinguishing water tanks.

A distinction is made between a dependent extinguishing water supply, which is provided by the hydrants of the public water supplier, and an independent extinguishing water supply which is not dependent on a pipeline system.

Dependent extinguishing water extraction points

Löschwasser Prüfung For their drinking and industrial water supplies, the municipalities provide water extraction points in the form of hydrants at close intervals. The required amount of extinguishing water is between 24 and 192 m³ / h, depending on structural use, usage density and the risk of fire spreading. According to DVGW and AGBF, the distances between the hydrants should be less than 150 m.

However, water supply companies are usually not legally obliged to ensure the required extinguishing water supply in whole or in part via the public drinking water network. In Germany, water supply companies therefore regularly refer to DVGW worksheet W 405 (Provision of extinguishing water by the public drinking water supply) with regard to the provision of extinguishing water.

As in other countries, companies in Germany can be obliged to keep a specified number of hydrants available on the factory premises by the respective municipality as the fire service provider and on the basis of the applicable fire service law.

The amount of water to be expected by the fire brigade that a hydrant can deliver depends on the diameter and the water pressure of the water pipe, as well as on the laying of the water pipes (ring pipe or branch / branch pipe). In Germany, the standard value for underground hydrants is assumed to be a yield of diameter × 10 l/min, and diameter × 15 l/min for post hydrants, the diameter being given in mm. In Austria, the supply of extinguishing water, like all fire protection, is regulated by state regulations.

Independent extinguishing water extraction points

Löschwasser Prüfung If it is not possible to ensure an adequate water supply due to the dependent extinguishing water supply, extinguishing water extraction points can be set up by the municipality at existing running or standing waters, or extinguishing water supplies can be provided in specially created ponds or cisterns. Since these water extraction points can only deliver a limited supply of extinguishing water under certain circumstances, they are divided into exhaustive and inexhaustible extinguishing water extraction points.

Exhaustible extinguishing water points have only a limited water supply. These can be extinguishing water ponds or special underground water tanks (cisterns). In Germany, extinguishing water ponds must have a minimum depth of two meters and a capacity of at least 1000 m³ and be provided with a suction shaft or a permanently installed suction pipe. Cisterns are divided into "small" (75–150 m³), "medium (150–300 m³)" and "large" (> 300 m³) according to their size. Barrages in streams, the inflow of which is not that large, are also among the exhaustive water points.

Inexhaustible extinguishing water points provide a sufficient amount of extinguishing water over a longer period of time. These include natural or artificially created water extraction points in open waters ("suction points"), such as rivers, streams or lakes, provided they guarantee water extraction at all times of the year, i.e. do not dry out in summer and do not freeze in winter.

The paved driveways must be accessible to vehicles with an axle load of 10 t in all weathers and the extinguishing water point must be usable immediately even in frosty weather. The suction height should be kept as low as possible and not exceed 5 m. The immersion depth (covering of the suction strainer) must be approx. 30 cm with a water flow of 800 l/min and at least 50 cm with 1600 l/min.

The extraction from the groundwater can also take place via special extinguishing water wells, here the flowing groundwater enables water to be extracted over a longer period of time.


Excerpt from extinguishing water well

Are artificially created extraction points for extinguishing water from the groundwater. The extinguishing water can be removed by suction (S) or by means of a deep pump (T).

Classification of the productivity of extinguishing water wells:

ProductivityIdentification numberl/min
Small 400 400 up to 800
Medium 800 over 800 up to 1.600
Large 1.600 over 1.600

It must be possible to provide the key figure quantities for a new setup over 3 hours.

Designation of a small extinguishing water well (code 400) with a deep pump:
Well DIN 14220: 2009-02 400 S

Designation of a medium-sized extinguishing water well (code 800) with a deep pump:
Well DIN 14220: 2009-02800 T

Building Code

State Building Code of the State of Baden-Württemberg Industrial Construction Directive
5 General Requirements

  5.1 Extinguishing Water Requirementsaugesetzbuch

For industrial buildings, the extinguishing water requirement must be determined in consultation with the department responsible for fire protection, taking into account the areas of the fire sections or fire fighting sections and the fire loads. It can be assumed that there is a need for extinguishing water over a period of two hours of at least 96 m3 / h for sections of up to 2,500 m² and of at least 192 m3 / h for sections of more than 4,000 m². Intermediate values can be interpolated linearly. For industrial buildings with an automatic fire extinguishing system, an amount of extinguishing water of at least 96 m3 / h over a period of one hour is sufficient for the fire brigade to extinguish the fire.

Fire Brigade Act

§3 tasks of the community

(3) Owners and owners of properties with an increased risk of fire or explosion or other special dangers can be obliged by the mayor to procure and maintain the equipment and systems required to combat these dangers and to have sufficient extinguishing water and other resources available. Owners and owners of remote buildings can be obliged by the mayor to set up and maintain extinguishing water systems for these buildings. Other legal obligations remain unaffected.

Notes on the performance of a community fire brigade from the Ministry of the Interior and the State Fire Brigade Association

In the course of the past year, a joint working group of the Ministry of the Interior and the State Fire Brigade Association checked and updated the information on the performance of a community fire brigade from 1999 to ensure that it is up to date. The notices have been updated and, in particular, considerations on cross-community planning have been included. One focus is the strengthening of intermunicipal cooperation.

In practical application, the information should help both when reviewing the existing fire brigade structure and when deciding on future concepts.

The notes can be used, for example, for:
  • The definition of the alarm and release order for a community fire brigade, also beyond community boundaries
  • Location decisions for fire fighting vehicles and equipment within a municipality
  • Vehicle and equipment procurement
  • The creation of cross-community vehicle concepts and cross-community procurement

A needs-based fire brigade planning, also taking into account cross-community help, not only serves an effective and cost-effective completion of tasks. It is also an important planning tool to defuse the problems of ensuring daily alarm readiness.

These notes are divided into three sections:


Each municipality has to set up, equip and maintain an efficient fire brigade appropriate to local conditions at its own expense in accordance with Section 3 Paragraph 1 Clause 1 of the Fire Brigade Act (FwG).


The lower the likelihood of occurrence, the more suitable is joint procurement within the framework of inter-municipal cooperation. If there is a high probability of occurrence in a municipality, this speaks more in favor of a municipality´s own procurement. In any case, it must be checked whether fire engines from neighboring communities can be included.


The fire brigades can also use the resources of other organizations and institutions. This must be taken into account in preparation for the deployment planning. It is forbidden to take this into account in the local fire brigade requirement planning if the availability of these units and equipment is not guaranteed around the clock and throughout the year.

DVGW worksheet W405 "Provision of extinguishing water by the public drinking water supply"

(1) Scope

This worksheet applies o to the determination of the extinguishing water requirement. It is to be used for the planning and construction of designated development areas and for building projects outdoors. o for checking the extent to which the extinguishing water can be taken from the public drinking water pipe network. It does not apply to measures under the Water Safety Act.

(4) Principles

According to the fire protection legislation of the individual federal states, fire protection is a task of the municipalities. The municipality must check which extinguishing agents should be used. If extinguishing water is required for fire protection, it must first be determined to what extent the extinguishing water can be taken from open watercourses, ponds, wells, containers (extinguishing water tanks, also container vehicles) or the public drinking water pipe network. The overall cheapest solution is to be determined.

(5) Basic protection

The extinguishing water requirement must be determined for the extinguishing area (see Section 7) depending on the structural use and the risk of fire spreading. The differentiation according to the structural use is made in accordance with Section 17 of the Building Use Ordinance.

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