Page 167 - CW E-Magazine (7-5-2024)

Special Report

Explosions of small LPG cylinders and their prevention

Background The government wants to make the ASHOK GUPTA
n India, “accidental” explosions of lives of urban and rural poor house- Email: k.ashok.g.@gmail.com
small domestic liquefi ed petroleum wives more comfortable through its
Igas (LPG) cylinders are frequently Ujjawla scheme of providing LPG in This author believes that most of
reported. Most of these cause serious every home. Many such homes are just these “accidents” can be, and must
damage to property and many lives are one room, including the kitchen, and often be, prevented. It will save hundreds of
lost. We refer to an answer(1) to a Rajya have an inflammable thatched roof. lives every year and prevent damages
Sabha question about LPG-related That may further increase the number to properties running into hundreds of
accidents by the Ministry of Petroleum & of LPG cylinder explosions. crores of rupees. As human lives are
Natural Gas (MoPNG). It gave the priceless, necessary safety measures
fi gures for the years 2016-17 and 2018-19. Purpose may be formulated and implemented by
Based on the figures quoted by The purpose of this document is to the concerned government authorities,
MoPNG, we estimate approximate look at the possible causes of frequent as soon as possible.
annual accidents in India at about 2,000 domestic LPG cylinder explosions and
or about fi ve per day. The approximate measures for the prevention of these Science behind explosions
compensation paid to victims of explosions. Explosions are caused by the sudden
domestic LPG explosion accidents was (within a few milliseconds) release of a
Rs. 22-crore in 2016-17. This author believes that India has lot of energy. Some common types of
ignored the following two standard man-made explosions and their causes
When considered on a per million safety rules, which are globally fol- are listed below. All the following four
LPG users basis, the accidents, deaths lowed for all pressurized liquid gas cy- types of explosions lead to high-power
and loss of property fi gures are dispro- linders (including propane and LPG): shockwaves, causing a loud sound and
portionately high in India compared  Prohibit storage and use of all such severe damage to surrounding struc-

with other countries. cylinders indoors; and tures and people.
 Provide a Pressure Relief Valve
The explanation given for these (PRV) to prevent the build-up of any Explosions may be caused due to
“accidents” is “LPG leakage as the pri- dangerously high internal pressure. excessive internal pressure inside a
mary cause”. This has been the offi cial tank, like in the case of steam boilers.
stand since the 1960s when LPG was If India also follows these two When the internal overpressure exceeds
fi rst introduced in India as a clean and basic safety rules for small LPG cylin- the bursting pressure, the envelope
convenient cooking fuel. However, this ders, most of these “explosions” will explodes violently. Remember that these
author thinks otherwise. be eliminated. Presently, these are explosions are caused only by force
kept indoors, usually under the kitchen exerted by the internal pressure of the
Let us consider the data(2) on home platform. In case of any fi re inside the fl uid inside. This mechanical effect is
fi res in 2017 in India as given by the kitchen or indoors due to any reason, independent of the nature of the fl uid
Govt. of India. It shows that the including any leakage of LPG, that may inside. Therefore, even water, steam,
total number of home fi res in 2017 was heat the LPG cylinder. This will cause air, and even any inert gas at any tem-
7,660, killing 7,614 people. It implies the LPG cylinder to explode, like an perature but suffi ciently high pressure
that if one excludes the ~2,000 LPG Improvised Explosive Device (IED). will lead to this type of explosion and
explosion-related fi res in one year, damage due to a catastrophic mechanical
as mentioned in the fi rst answer by At present more than 400-mn small failure of the envelope.
MoPNG, approximately 5,660 home LPG cylinders are in circulation. Most
fi res in that year were not related to of these are kept and used in kitchens Explosions may be caused due to
LPG cylinder explosions. Had there or indoors in India. With nearly 8,000 a fast exothermic chemical chain reac-
been any LPG cylinders in these ~5,660 home fi res reported every year in India, tion; e.g., when an explosive mixture
homes and if these were exposed to the the potential danger of LPG cylinder of any fuel and oxidizer (air) is trig-
heat of the home fi re, many of those explosions and resulting loss of lives gered by any spark or hot surface, as in
cylinders may have also exploded. and property is huge. the case of gunpowder, TNT, or LPG.

Chemical Weekly May 7, 2024 167

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