Industrial, Warehousing and Manufacturing

Sprinkler systems are widely recognised as the single most effective method of fighting the spread of fires in their early stages in industrial and manufacturing occupancies. In addition to protecting the property, they may also serve for the protection of life.

The financial burden of buildings and contents insurance can be greatly relieved by the provision of sprinkler systems and companies often recoup the cost of the system within twelve months with their reduced insurance premium.

Hazard identification and classification provides the basis for the design of the sprinkler system and is a skilled operation, which is usually carried out by the Insurer or Fire Authority. The hazard classification affects the choice of installation, operational method, water supply arrangements and pipe work design.

Industrial occupancies that typically have abnormal fire loads within them and are classified as high hazard and sub-classified as:

Process high hazards
High piled storage high hazards
Potable spirit storage hazards
Oil and flammable liquid hazards

Process high hazard is applicable where the occupants use materials mainly of a hazardous nature and which are likely to develop into rapidly and intensely burning fires. Typical examples of process high hazard types are shown in table below, which are from BS 5306. Type 1 is the least severe, while Type 4 is the most severe.

Table 4: Process high-hazards showing typical examples of types

Type 1

Type 2

Type 3

Type 4

floor cloth and linoleum manufacture

fire lighter manufacture

cellulose nitrate manufacture

firework manufacture

paint, colour and varnish manufacture

manufacture of category III (see table 2) foam plastics, foam rubber, foam plastics goods manufacture and foam rubber goods manufacture excluding category IV (see table 2)

 

 

rubber substitute manufacture

tar distilling

 

 

wood wool manufacture

 

 

 


The density of discharge for the sprinkler system can be established using this table. High piled storage is applicable where the occupants are storing goods of low to moderate risk, usually within beam pallet racking, shelving and post or box pallets. Freestanding goods stored to a certain height also fall within this classification. In order to determine a density of discharge for the sprinkler system, the goods stored must first be categorised.

Potable spirit storage hazard is applicable where the occupant is storing spirits, not in racked barrels, to heights exceeding those given in column 3 of the table . This is classified as high piled storage and is given storage Category 2 or 3.

Oil and flammable liquid hazard is applicable where the occupant is storing oil and flammable liquid in such quantities and in such a manner that standard sprinkler protection may not be effective. In these cases, a deluge installation using high velocity sprayers may be effective. Normal sprinkler installations may incorporate deluge systems to cover small areas of flammable liquid hazards.

Beam pallet racking
The storage within the rack is clothed in cardboard boxes. The cardboard element of the storage means that it is classed as Category 2 goods. The racks are type S5 and are 1 metre high, which means that in-rack sprinkler heads would need to be fitted, as roof protection would be inadequate.

A flammable liquid hazard
In this case, the liquid petroleum gas tanks are protected by a deluge system, which is an effective way of stopping a fire in one tank spreading to the others. Deluge systems also serve to damp down shockwaves produced by explosions and the cooling effect the mist-like spray gives has been put to good use, particularly on oil rigs and tanker unloading bays.

Typical type S1 or freestanding storage
Whey storage - to a height of 3 metres. Whey is classed as Category 2 goods and if only stored to 3 metres, ordinary hazard protection is adequate.

Category 2 goods, stored in S5 type racking
In this case, due to the way the racking itself has been constructed, it is impossible to install sprinkler heads within the rack structure. As a result, the sprinkler pipe work has been designed and positioned to provide a higher discharge density over the stored goods, to compensate for the lack of protection within the racks.

As you can see, the type, size and design of the sprinkler system is flexible so that the protection is appropriate to the hazard.

In all industrial applications, wet pipe installations are preferable. However, if the temperature of the premises cannot be guaranteed to remain above freezing at all times, an alternate system should be fitted; where only part of the premises may fall below 5°C during the winter, a tail end dry extension should be installed in that part as an extension to the wet installation.

Although local water authorities have a duty to supply water for domestic services, water supplies for sprinkler systems are provided only on request and are rarely adequate for high hazard industrial applications. Therefore, a dedicated, dependable supply usually has to be provided by means of a duplication pump set and storage tank.

If you would like any further information regarding sprinkler systems for industrial premises, please call 01769 574070 or email fds@fire-defence.com

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