In case of godowns containing baled raw jute, an aggravating factor is the burning characteristic of the material. Godown fires are most stubborn and difficult to extinguish. When an outbreak occurs in a jute godown, fire spreads over the surface of the bales with great rapidity, at the same time working its may between the bales until the whole mass is involved. The losses arising out of fires in Jute Godowns are enormous and it is much more than the fire losses in the manufacturing departments. fire occurring in the jute godowns, also burrows within the bales and after travelling through interstices of the stacks continue to burn merrily in isolated pockets where extinguishing water jets or sprays cannot readily reach. Jute fibre has also a tendency to shed water and rapidly dry up during a fire. It is, therefore, not unusual to find water soaked fibres re-igniting after a few minutes. Because of these features it usually takes hours to extinguish a jute godown fire and in the process thousands of gallons of water have to be used.
The fact that jute emits a dense and acrid smoke while burning which constitute a major hazard and great handicap in fighting a fire in a jute godown.
Another important hazard of jute godown fire is due to characteristic property of jute in absorbing large volumes of water, and the consequent swelling accompanied with it. Fully soaked jute absorbs more than its own weight of water. The swelling pressure in case of pucca bales may be as high as 4,600 pounds per square feet. In the past, this has brought down 20 inches thick brick walls where bales were stacked either against the walls or with very little clearance therefrom. In case of piles of kutcha bales, the swelling has resulted in collapse of high stacks.
A remarkable feature in case of jute godown fires has been the discovery of the outbreak in many cases, after some hours the godown being closed or locked. This at a time led to a general belief that external source of ignition could not have been the cause. It was thought that these fires were caused by spontaneous combustion. However, research conducted in India and abroad have proved that jute is not susceptible to spontaneous combustion unless it is contaminated with oil, grease and similar substances. In fact, however, uncontaminated, jute is not liable to ignite spontaneously. Tests have proved conclusively that a temperature of about 482*F is necessary before combustion will take place, but the maximum temperature generated by the self healing of uncontaminated jute in bulk never exceeds 158*F. Since most of the godowns do not use artificial lighting, the largest caruse of fire in godowns is believed to be due to careless disposal of smoking material, if not arisen out of malicious causes. The prohibition of smoking has long been the rule within the jute mill premises, but inevitably some surreptious smoking has always taken place. This is a matter of good management and discipline, but “no smoking” is a difficult rule to enforce at all times.
FIRE PROTECTION IN JUTE GODOWNS
Because of high incidence of fire in jute godowns resulting in heavy losses, the fire protection systems with its merits and demerits should be discussed in detail.
EXITINGUISHING FIRE PROTECITON SYSTEMS
Most of the Jute Mills are protected with hydrant and sprinkler installations. Some others are protected with hydrants only while the remaining few have no protection. In spite of the protective measures, however, damage suffered by the contents of Jute Godowns are invariably of larger order. What is more distressing, specially in case of sprinklered godowns, is that more loss is caused by application of water than those due to fire itself. Two factors viz. (a) operation of unnecessarily large number of sprinkler heads and (b) rather indiscriminate application of water jets by Brigade personnel are the reason for this state of affairs.
LIMITATIONS OF SPRINKLER INSTALLATION
Naturally the question arises whether sprinklers are really efficient system of fire protection for tacking jute godown fires. To be truthful it must be conceded that sprinklers have not proved to be as effective as in case of other numerous type of occupancies. In spite of insurance inducement to store smaller stocks as much jute as possible. Furthermore, there is no limit to size of individual piles. Only in case of a sprinkler protected godown, if stack height exceeds 18 feet 6 inches, a reduction of 5% discount is recommended in the Tariff. As godowns on an average are of 25 to 30 feet thus making possible stack heights of over 20 feet. As a result a fire breaking out and burning in isolated pockets at the bottom of the stacks takes longer time to be detected and does not receive the spray, from the sprinkler heads. At the same time, the fire flashing over the end-to-end stacking opens a large number of sprinkler heads, thus reducing the operating pressure and the spray efficiency.
A second cause of operation of large number of sprinkler heads is inadequacy of smoke and heat ventilation facilities. Jute godowns are generally ventiliated by goose-necked or similar ventilators at roof levels. In some other cases, wire-mesh protected ventilation openings are provided near the top of the walls. Although the existing ventilation facilities may be adequate under normal conditions they appear to be totally inadequate for quick release of heat and smoke during a fire. As a result the accumulated heat at roof level spreads laterally to other portions leading to unnecessary operation of sprinkler heads over stocks unaffected by the fire.
The sprinkler system would have given a much better account of itself had the size of individual jute piles been limited and they be surrounded by longitudinal and cross aisles of adequate width. Even under present conditions the sprinkler system performs a very valuable service which is often not realised. This is the protection they afford to the building structure of the godowns. There is no doubt that in case of many jute godown fires the total losses would have been considerably aggravated by building damages, but for the sprinkler protection.
ACTIVITIES OF FIRE BRIGADE
Turning now to the Fire Fighting tactics of the Fire Brigade one quite often has to listen to the complaint of indiscriminate use of water jets by Fire-men, Indeed, on quite a few occasions, it had been reported that Fire Service personnel had refused to heed to Mill Staff’s advices regarding the location of the seat of fire and continued to direct their water jets to all parts of the godown. While in some cases, the Mill Staff’s grouse do have sound basis, often the difficulties of the Fire Service personnel are overlooked.
Due to lack of adequate smoke ventilation facilities, jute godowns get severely smoke logged at very early stages of an outbreak. In those cases where fires break-out in locked godowns, (which most frequently is the case), it is almost impossible to locate the seat of fire. Being aware of the heavy storage and high and frequently unstable stacking conditions within the godown it becomes difficult for the Officer-in-Charge to ask his men to go inside smoke filled godown looking for the seat of fire, under extremely visibility conditions. It is, however, impossible that in quite a few cases Fire Brigades’ task would have been easier had Breathing apparatus been provided to the Firemen. But due to limited number of such apparatus being at the disposal of the Fire Services their use is entirely restricted for fighting chemical fires or fires in holds or ships. It is the comparative shortage of equipment and manpower which is probably another cause of the indiscriminate use of water by the Fire Brigade men. There seems to be an unwritten directive that the fire must be extinguished as quickly as possible and the fire men return to their respective stations at the earliest moment to await the next call.
Another feature which has led to undue water damage to contents in some cases is lack of adequate number of doors for the godowns. Quite a number of Jute godowns have only a single door at one end. Consequently, when the seat of fire is located at the remote end of the godown the Fire fighters have no alternative but to direct hose jets from the door end due to which unaffected stocks also get water damaged.
Water, has been and will yet remain the principal fire extinguishment in ordinary combustibles. Some water damage is, therefore, to be expected. Fire fighting tactics, however, should be so oriented as to keep this damage within limited bounds.
A point that deserves mention in respect of water damage aspects of Jute Fire problem is that no attempt is made for recovering of an efficient salvage corps whose duties would be to protect undamaged goods in course of an outbreak helps in reducing the water damages to a considerable extent.
OLD PRACTICE OF FIRE FIGHTING
In bygone years when Services of Fire Brigade were not so readily available in many places, somewhat different fire fighting procedures were followed for sprinklered godowns, than those practised now. At the sounding of the alarm, the Mill staff used to seal up all ventilation openings and gaps underneath doors with mud and allowed the sprinklers to tackle the outbreak. The godown doors were opened from time to time to ascertain interior conditions and after the blaze had died down appreciably smouldering pockets of fire were extinguished with water jets. Many people feel that this method of fire fighting caused far less water damage. Undoubtedly, in a number of cases tackled in the above manner, appreciable amount of stocks had been recovered in undamaged condition. However, it would be dangerous to be too dogmatic on this score. For, in a number of other cases entire stocks had been affected. One great disadvantage of the older method was that it often took several days to completely extinguish the fire.
NEW FIRE EXTINGHISHING MEDIUMS
As stated before, water has to the principal fire extinguishing medium for jute fires, because of its effectiveness, cheapness and abundancy. However, during the last few years experiment with some other media have been conducted in U.S.A. and U.K. Notable among them are CO2, inert gases generated by burning of oil fuels and High-Expansion Foam. Indeed in one case in U.K. a basement fire amidst stocks of jute bales was successfully fought with the help of CO2. In this case, carbon-dioxide gas was used to supplement the sprinkler protection and a large amount of unaffected stocks was recovered. However, it is doubtful whether this mode of fire fighting would be economical and practicable in our country at present. This is because, by the time the blaze was extinguished 2-3 tons of CO2 had to be used and several tanker loads of CO2 had to be requisitioned from gas manufacturing concerns.
As regards inert gas, the same has been successfully tested in case of different types of fires and a type of turbe-jet engine is now being produced in U.K. in a commercial scale. Authoritative sources are however, not unanimous as to whether this form of fire protection would be effective against jute fires.
It is the third of the three media mentioned above viz. High-Expansion Foam, which seems to hold greatest promise as a future extinguishment medium of jute godown fires. A number of experiments have been carried out in U.K. and the results are reported to be most encouraging. However, it is felt that many more experiments are called for before an authoritative verdict may be given.
As water would still be the extinguishant in almost all cases of jute godown fires, means must be found to improve its effectiveness and reduce the losses inherent in its use.
As far as sprinklers are concerned as stated earlier thought is already being given to designing of systems capable of dealing with high piled storages.
The water damages due to indiscriminate use of water jets, however, is more important. Such damages may be appreciably reduced if it is made easier for the Fire Services personnel to locate the site of Fire and enter the godown. This may be done by the following measures :
(a) Provide sufficient manually operated smoke hatches of 6’ x 4’ sizes so that at least 1 sq. ft. of ventilation opening is provided for every 50 sq. ft. of floor area.
(b) Provide approved type of automatic fire alarm system, the annunciator boards of which would indicate in which portion of the godown the fire is located. Such alarm system may be installed in conjunction with a sprinkler system.
(c) Provide adequate number of doors to the godown with a minimum of two to each godown.
(d) Limit the size of the individual jute piles to 50’ x 50’ x 15’ and separate the piles by longitudinal and cross aisles of 6’ and 4’ width respectively.
(e) The Fire Service personnel attending Jute Fires should have at least two Breathing Apparatus.
(f) Exhort the Fire Service personnel to reduce the water damage as far as possible.
(g) Constitute an independent salvage organisation working on a non-profit making basis. Duties of the staff of such a salvage corps would be to help the Fire Services in whatever manner possible and salvage the damaged stocks both during and after an outbreak.
Bad loss experience in the jute industry since inception led the underwriters to think about the possible steps which can be taken to minimise the large losses and in fact, these thinkings have been expressed in the form of various warranties applicable to Jute Mills and Press-premises as laid down in the Tariff. Also, the processes prior to spinning, and sack sewing, singeing being comparatively more hazardous than the processes of spinning and subsequent to that, carry a lower rate of fire insurance premium. Dust Shaker machines in which highly inflammable jute wastes are processed, are generally installed in a separate room isolated from other sections.
Since the quantum of losses in godown is directly proportional to the quantity of jute stored in the godown, one warranty restricting the storage of jute has been stipulated in the Tariff. The rate of fire insurance premium are higher in case of jute godown storing jute the quantity of which exceeds the quantity stipulated in the particular warranty.
Because of this warranty, the insured would be more interested to store jute within the prescribed limit as per the Tariff rather than to pay extra premium. In fact, the large sized godowns in most of the mills were divided into two or three separate godowns each separated from the other by perfect party walls so as to comply the warranty. As a result the maximum loss arising out of a fire in a particular jute godown is reduced to a certain extent. There is another warranty which prohibits the storage of jute in the open within 22.50 metres from the jute godown. The exposure hazard of a fire in open jute storage is very high and fire arising out of it may affect a building situated far away from the open storage. By the application of these warranties, underwriters try to minimise the losses arising out of a fire. Certain warranties which prohibit smoking or cooking in Jute Mills and godowns are applicable in order to prevent the occurance of fires by eliminating sources of ignition. A number of warranties are applicable to both manufacturing sections and godowns. Certain warranties must be complied with at all the times, while provisions are there in the Tariff for acceptance of the insurance cover by collecting additional premiums for deletion of certain other warranties.
The basic fire rate depends on the class of construction of the buildings according to the classification provided in the building regulations in the Tariff and occupancy. Underwriters are aware of the hazards of the Jute Industry and a number of factors for minimizing/preventing losses are considered in arriving at the net fire insurance premium. For example, if a jute godown is protected by approved hydrant as well as automatic sprinkler installation, the F.E.A. discount may be as high as 45%.