EXTINGUISHERS

    

General

Extinguishers are essentially first aid fire fighting appliances.

Nevertheless, these are very valuable if used promptly and efficiently in the early stages of a fire. In addition to the value of their portability, the most important feature of these extinguishers is their immediate availability so that each extinguisher can be used by one person.
The usefulness of these extinguishers is limited as it is entirely dependent upon the presence of persons having knowledge to operate them. Furthermore their capacity is also limited and their operational value largely depend upon the initial charge being sufficient to overcome and confine the fire. The capacity of such extinguishers should be commensurate with the risk these are intended to cover.

Since a variety of shapes or methods of operation of fire extinguishers have at times, led to confusion, and failure to quench the fire, it is recommended that extinguishers installed in any one building or single occupancy shall be similar in shape and appearance and should have the same method of operation, as far as possible. This will also simplify the training of the large number of workers in the effective and efficient use of extinguishers.

Fire extinguishers shall be provided both for protecting building structure as well as occupancy hazard contained therein.

The number and size of fire extinguishers required for any particular premises shall be determined by the appropriate authority taking into consideration the severity of incipient fire anticipated, rapidly with which a fire may spread, intensity of heat that may be developed, accessibility to fire, type of extinguisher, the smoke contributed by the burning material, special features of building construction and nature of occupancy (single or mixed), and electrical fittings, equipment etc., installed therein.

The required number of portable fire extinguishers may be determined by considering any single extinguisher of suitable type or a combination of two or more types. Recommendations made in Appendix A may be taken as a guide.

When selecting locations for fire extinguishers, due consideration should be given to the nature of risk to be covered. The extinguishers should be placed in conspicuous positions and shall be readily accessible for immediate use in all parts of the occupancy. It should always be borne in mind while selecting locations that fire extinguishers are intended only for the use on incipient fires and they will be of little value if the fire is not extinguished or brought under control in the early stages.

Generally, portable fire extinguishers should be placed as near as possible to exits or stair landings wherever possible, advantage should be taken of normal routes of escape by placing these in positions where these shall readily be seen by persons following the natural impulse to get out of danger.

It is not advisable to place extinguishers at the ends of rooms remote from exits unless such distribution is necessary to cover a particular hazard. The extinguisher should be visible and easily accessible and the passage leading to them should always be kept completely unobstructed.

A framed plan showing the location of fire extinguishers, means of access and other useful information should be displayed at suitable places.

General

Although portable fire extinguishers are not permanent and immovable fittings in a structure, these form a part of the whole system of fire protection and should receive consideration at the design stage. In some cases, it may be necessary for the extinguishers to be housed in readily accessible and unlocked receptacles, where although clearly visible, these should be unobtrusive. Cognizance should be taken of any statutory order, local by-law or other requirements with which compliance is essential.

Time Schedule

Excepting particular cases where, as stated in a), it may be necessary for the extinguisher to be housed in specially prepared positions, no structural work is generally involved in the installations of the extinguishers dealt with in this standard as this normally takes place upon the completion of the construction. The General sequence of the building operation is not, therefore, usually effective. Where a special recess is to be formed in a wall, provision should be made as the work progresses.

Selection Of Fire Extinguishers

Various types of fire extinguishers specified in this standard are of value but are all not equally effective on all types of fire. For this reason, the nature of contents of a building, the process carried out therein and the types of fire, which may occur, shall be taken into consideration while selecting fire extinguishers.

For all practical purposes the basic types of fires can be grouped into following four classes :

• Class A Fires

Fires involving combustible materials of organic nature, such as wood, paper, rubber and many plastics etc., where the cooling effect of water is essential for extinction of fires.

• Class B Fires

Fires involving flammable liquids, petroleum products, or the like, where a blanketing effect is essential.

• Class C Fires

Fires involving flammable gases under pressure including liquefied gases, where it is necessary to inhibit the burning gas at fast rate with an inert gas, powder or vaporizing liquid for extinguishment.

• Class D Fires

Fires involving combustible metals, such as magnesium, aluminium, zinc, sodium, potassium, when the burning metals are reactive to water and water containing agents, and in certain cases carbon dioxide, haloginated hydrocarbons and ordinary dry powders. These fire required special media and techniques to extinguish.

Suitability Of Portable Fire Extinguishers

The types of extinguishers mentioned below against each class of fire are generally most suited. Details of suitability as a guide of each type of extinguisher is shown in Table I. It may, however, be noted that this is only for guidance and does not cover special cases.

• Class A Fires

Water expelling type extinguishers.

• Class B Fires

Foam, dry powder, vaporizing liquid (at present there is no Indian Standard covering this type), carbon dioxide extinguishers.

• Class C Fires

Dry powder and carbon dioxide extinguishers.

• Class D Fires

Extinguishers designed for expelling special dry chemical powder.

Work On Site

Work on site mainly consists of charging the extinguishers where necessary, and placing these at appropriate location.

Each new extinguisher should be charged with the ' refill ' provided with it in accordance with the instruction given on the refill container. This however does not apply to the carbon dioxide extinguishers which are available fully charged.

All refills should conform to relevant Indian Standards.

All bucket pump type extinguishers should be filled with clean water before being placed in position.

All new extinguishers should be wiped clean from the outside and the brass parts should be polished with metal polish. Care should be taken to ensure that the nozzle outlet or the vent holes provided in the screwed portion of the cap or shifter valve or vent holes, if provided, do not get clogged.

Where applicable, hose and nozzle connections should be checked to ensure tightness of joints.

Each first aid fire extinguishers should be allotted a special number by which it shall be referred to in the records. The following details should be painted with white paint on the body of each fire extinguisher :

1. Serial number,
2. Date of last refilling, and
3. Date of last inspection.

The details should be repainted each time the extinguisher is refilled or inspected.

Once the location of each extinguisher is decided, these should be fixed or placed in position as given below :

1. In Open Area

Fire extinguishers should be placed on masonry platforms or in wooden or metal cabinets in such a way that their bottom is 750 mm above the ground level.

Where cabinets or sheds are used to house the extinguishers in the open, these should be so designed that removal of these extinguishers are not hampered in an emergency.

2. Inside a Building and Under Cover

Fire extinguishers whether hung on brackets or kept on shelves should have their bottom 750-mm above the floor level.

In no case a fire extinguisher should be places in a position where it is likely to gain heat from the surrounding equipment or the process.

TABLE - I

Suitability Of Different Types Of Fire Extinguishers For Different Class Of Fires

Maintenance, Inspection And Testing

Routine maintenance, inspection and testing of all fire extinguishers in respect of mechanical parts, extinguishing media and expelling means should be carried out by properly trained personnel at frequent intervals but atleast once in a month to make sure that these are in their proper condition and have not been accidentally discharged or lost pressure or suffered damage.

At a longer interval, atleast once in a year, a more thorough inspection and maintenance of extinguisher, including chemical charge inside and expellent should be carried out by trained personnel, according to the procedure given below for each type of extinguisher separately. Any extinguisher showing corrosion or damage to the body internally or externally should be replaced. Faulty, damaged and corroded parts shall be replaced by correct component. Illegible labels should be replaced.

The inspection and maintenance of extinguisher is designed to ensure that the extinguisher will remain as reliable during the whole service as when new. But it is not desirable that extinguisher should remain in service indefinitely without more thorough test as in some cases, such as chemical foam, dry powder etc., the extinguishing media itself is liable to deteriorate and should be periodically replaced.

The performance tests on 50 percent of each type of extinguisher shall be carried out in accordance with relevant Indian Standard at intervals.

The pressure or leakage test of all types of extinguishers shall be carried out at intervals.

The rejected bodies of the extinguishers should be destroyed, so as to prohibit their subsequent use.

Records

The records of maintenance, inspection and testing of all first-aid fire extinguishers should be maintained in the register (Appendix B). One page should be allowed to each extinguisher.

A P P E N D I X - A 

Recommended Scale Of Portable Fire Extinguishers For Different Types Of Fire Risks

Types  And  Capacity  Of  Various  Extinguishers

Projects & Credentials

• Consultancy
• Maintenance
• Project Job
• Supply