The industrial equivalent is the explosive consequences of accidently adding water into molten metal, temperatures

Posted 4 Dec 2011

Sometimes American standards of precautions to control fire and explosion hazards leave me just amazed: ‘how could they do this?’ Two examples from the www.csb.gov website are worth highlighting.

The most recent comes from a csb report released in Oct 2011. This has an analysis of incidents at small oil production sites. These often have above ground storage tanks for oil products together with a nodding donkey. These isolated wells are unmanned but pump away slowly, until the surface tank is full and a tanker takes the product way. Evidently many are unfenced, and have no signs to indicate that they contain highly flammable oil or gas. Even more alarmingly, they often seem to have unlocked tanker hatches, with no flame arrestor. A match or cigarette nearby can then literally cause the tank to explode. Evidently California legislated to control the risks back in 1983, but other states did not follow and 44 members of the public have been killed since then.

An explosion which killed 6 people and injured 50 others occurred during planned work to clear debris from new assembled large diameter pipework at a gas fired power plant nearing the completion of construction. Natural gas at 45 bar was deliberately released from a vent just 6m above ground level in a congested area. Controls over ignition sources were minimal. 56,000 m3 of gas were released in 15 such gas blows during a single morning. 7000m3 of this gas was released in  10 minutes leading up to  the explosion.This was evidently common industry practice, not a rogue set of installers. A similar event had killed 4 and injured 67 just 8 months earlier.

‘Elf and Safety has an image problem in the UK, but someone has to provide an independent view of safe working practice, or we will kill workers and the public for lack of the simplest of safety precautions.

Posted 15 Aug

Some companies choose unfortunate names

Some people never read or follow instructions

Some products invite misuse

So when a company calls itself Bird Brain Inc, and sells a liquid fuel thickened so it forms a gel, perhaps we should fear the worst. At least it has not called its product napalm, but it might as well have done. It is based on isopropanol, and is probably easier to ignite than napalm, which is formulated to make it relatively safe to handle. See www.explodingfirepot.com/birdbrain-lawsuit/ to read what can happen when people don’t understand the dangers, and then ask what would happen if this got into the hands of those who wanted to cause danger and injury to others.

Do we need this stuff?

The explosion and fireball on the 13th July at a small industrial unit in Boston Lincolnshire has been widely reported to be the result of an illegal plant distilling alcohol for sale as vodka. 5 people were killed immediately.
The details of the process are not available at this time, but we do have an estimate of the size of the industrial unit where the plant was located. This has been reported as having a floor area around 50 m2, so perhaps has an internal volume of 200 m3. With a LEL of 60g/m3, a release of just 12kg of alcohol as vapour could entirely fill this unit with an explosive mixture. Loss of cooling to the still or fracture of a hot part of the equipment are the most obvious possible causes.

19 July 2011

Powder coating plants do not appear often in the records of dust explosions, but the hazards are real, and much work was needed to ensure the equipment works safely. The original version of standard EN 50177 dating from 1997 contained an odd mixture of requirements for the equipment suppliers, requirements which depended completely on the user, and some statements that seemed just like wishful thinking. It has just been updated and republished as BS EN 50177_2009. Flock processes also present explosion hazards, though the materials are difficult to test in the way that dusts are evaluated. The recent publication BS EN 50223:2010 is an product standard that covers the hazards of electrostatic flock processing equipment.

03 May 2011

Standards work on mechanical equipment for explosive atmospheres.
This issue comes from a meeting in Stockholm on the 5th April.

Independent testing in the UK of electrical equipment used in places where there was an explosion risk long predates any specific law requiring this, and similar independent testing was done in other European couintries. The ATEX equipment directive, adopted in 1994 was intended in the first place, not to increase the safety of such equipment, but to ensure that manufacturers only had to have it tested once, in order to sell it freely across Europe.

The ATEX directive did however increase the range of equipment that had to meet defined safety requirements, but without insisting that everything was 3rd party certified. The vast majority of mechanical equipment in scope is certified as safe by the manufacturer.

Along the way, the standards have become world-wide, through the IEC, rather than European, and the objective of a single test certificate valid across the world is being achieved for electrical equipment through the IEC Ex scheme, which runs in parallel with European certification. The IEC Ex scheme is policed by peer review of work of the test houses which are members. They actively issue certificates for electrical equipment for ATEX category 3, which does not need such certification in Europe.

European standards for ATEX mechanical equipment are now being revised to make them into ISO standards, with the work closely linked to the IEC technical committee which writes the Ex electrical standards. There is real pressure to make the new ISO standards in a form which will suit the 3rd party certification process, though there is no tradition anywhere around the world for such certification.

There are some sharp questions here. Is there a wish or need from equipment manufacturers for certification? Will it help them sell their products more easily around the world, or result in costly design modification for little apparent benefit? For the users, would they welcome a certificate which gave them more confidence that they were buying a safe product? How much extra would they be prepared to pay for a 3rd party certified product? Is there a real market for certified equipment either for the gas and vapour applications, or the dust explosive atmosphere applications? Is this simply a means by which the test houses can extend the scope of their business? Will there be any identifiable improvement in safety?

Views from all sources welcome, please let me know what would be right for your business.

Alan
8 April 2011