Mine fires and explosions : the most devastating industrial disasters.

Fires and explosions pose a constant threat to the safety of miners and to the productive capacity of mines. Mine fires and explosions traditionally have ranked among the most devastating industrial disasters. The prevention and control of fire and explosion in mines is fundamental. On a mine site, fire hazards may occur in and around process plants, underground conveyors, static and mobile plants, draglines, workshops, substations, monitored control rooms and switch rooms. All mines have highly expensive and mission critical equipment that typically operate day and night under extreme hostile conditions, in vast, remote and difficult to access environments, especially on underground equipment. In many cases non-gaseous and gaseous fire suppression systems are the preferred systems installed to protect the high value assets, safeguard operators and processes so as to guarantee business continuity. However, it can be argued that the competitive nature of the free market places great pressure on the fire industry to deliver systems which minimally comply with, rather than exceed, the regulations. Too often fire protection is seen as a cost - not a vital investment for business continuity. High value assets such as critical mining infrastructure, may have catastrophic results in the event of downtime or shutdown due to fire. The risk far exceeds the risk of choosing minimal compliance, instead of advanced real-time monitoring systems. The cost or damage to reputational integrity as a result of this downtime far exceeds the cost of integrating a real-time monitoring system.

Regulations for fire protection/p>

The Health and Safety Executive clearly outlines that in 213. Regulation 9 of the Coal and Other Mines (Fire and Rescue) Regulations 1956 there is a requirement of managers of coal mines to put in place arrangements to ensure that: 35 • All fire-fighting equipment is inspected by a competent person at intervals not exceeding 30 days; • Each fire extinguisher is discharged and refilled by a competent person, at intervals not exceeding those specified by the manufacturer or supplier. The Fire Protection Association Australia states that the entire area should be a completely enclosed structure of fire resistant construction. This is particularly important for mines with intended for use longer than 6 months. If such an arrangement is not possible, then the area should be protected throughout by an automatic fire suppression system. In coal mines it is critical to minimize any potential fire source. In many underground mines, mobile equipment is typically diesel-powered, and a large percentage of the fires involve the fuel used by these machines. These fire hazards are compounded by the presence of coal, coal dust and methane.

What is a gaseous suppression system?/p>

Gaseous fire suppression systems typically encompass extinguishing agent stored in pressurised cylinders that are connected to a network of discharge pipework and nozzles that deliver the extinguishing agent to an enclosure to be protected.

Among the commonly used gaseous fire suppression systems are Carbon Dioxide (CO2) and Clean Agent systems which are both non-conducting fire extinguishants safe for use when dealing with delicate electrical and electronic equipment unlike water-based systems. Both CO2 and Clean Agent systems vaporise easily and do not leave a residue upon evaporation.

Clean Agents consist of two types which are halocarbons that are stored as liquefied gases and inert gases that are stored as non-liquefied gases. Halocarbon is a name given to compounds containing both carbon and at least one of the halogens (fluorine, chlorine, iodine or bromine). In the case of Halon 1301 and Halon 1211 which contain bromine, they possess strong ozone depletion potential that has been banned under the Montreal Protocol in 1989. Replacement halocarbons has since been developed using safer halogens such as fluorine and among the popular ones are NOVEC™ 1230 by 3M™ and FM-200™ by The Chemours Company. On the other hand, inert gases are clean agents that consist purely of inert gas such as Nitrogen, or a combination of gases in the case of Inergen which contains CO2, Nitrogen and Argon.

How Gaseous Systems combat the Fire Triangle

At the heart of clean agent extinguishing properties is the commonly used “Fire Triangle” that represents the three components required to start a fire which are oxygen, heat and fuel. When one or more of these components are missing, the fire will be extinguished. Halocarbon clean agents such as NOVEC™ 1230 and FM-200™ remove the heat component which effectively prevents the material from reaching its ignition temperature. CO2 and inert gases works differently by removing the oxygen component but equally as effective to extinguish a fire.

The clean agent systems function on a total flooding principle and are highly relied on due to their quick detection of a fire event, rapid suppression and extinguishment capabilities. Typical applications include chemical storage areas, clean rooms, communications facilities, robotics, emergency power facilities and in mining sites as well. Depending on the site, the installed clean agent systems are located in or around the fire risk areas such as control rooms, data centres, electrical switch rooms, and process control rooms.  All fire equipment and systems including gaseous fire suppression systems need to be regularly tested, serviced and maintained to help ensure that they will be ready to operate as intended at the event of a fire.

Why should we monitor them?/p>

Clean agent fire extinguishing systems of this type are governed by BS EN ISO 14520 Gaseous Fire Extinguishing Systems. They are designed to provide a supply of gaseous extinguishing medium for the extinction of fire. It is essential that gaseous extinguishing systems are carefully maintained to ensure instant readiness when required. Routine maintenance is liable to be overlooked or given insufficient attention by the owner of the system.  These are very highly pressurised systems often stored at pressures of 725 psi (50 bar) and above. In engineering terms, they are “dynamic” systems, not passive ones. Inspection preferably by a third party, should include an evaluation that the extinguishing system continues to provide adequate protection for the risk (protected zones, as well rooms built for room integrity, can change over time as they age or are modified).  There exist very few engineers in our industry who fully understand the design, installation, testing, maintenance and safety of gaseous firefighting systems in buildings, plants or other structures, and the characteristics of the various extinguishants and types of fire for which they are a suitable extinguishing medium.  The HSE states that, in mines, continuous monitoring and protection of machinery and equipment can significantly reduce the likelihood of a fire occurring by detecting abnormal operating conditions and generating a warning and/or stopping the machinery or equipment before it becomes a hazard. The same should therefore go for the gaseous systems.

Gaseous extinguishing systems are pressurised, and therefore exist in a dynamic state and can leak. As supported by the BS EN ISO 14520 regulation, if clean agent cylinders leak beyond 5% of contents or 10% of pressure they will not extinguish a fire event, as they will be below their design concentration.  As the “gold standard” of clean agent systems – BS EN ISO 14520 highlights the asset owner’s responsibility to check that the clean agents contents exist; that the protected space can be sealed; that the pipework used to discharge the clean agents are clear of particulates that can clog up the nozzles which reduces the amount of clean agent to the point where it cannot deal with the fire event.

Anecdotes of bad practice across all safety critical industries/p>

  • Low labour rate servicing crews being unskilled, unreliable and untrained
  • Disreputable companies randomly checking a few cylinders and placing “tested stickers” on the rest of the untested ones
  • 20% of marine CO2 cylinders installed have leaked or partially discharged during the course of their lifetime  

These anecdotes represent observations across multiple safety critical industries such as shipping  and could very highly be applied across the mining industry. These issues would risk the integrity of mining operations, because in the event of fire, there may be insufficient agent to extinguish it. For such safety critical operations, leaving fire safety systems unsupervised and unmonitored 364 days a year until their annual certification check is just too risky.

Industry trend to govern “the ungoverned space” /p>

Safety is becoming recognised as an area which must no longer be overlooked. The industry is beginning to opt for more regular inspections and even, continuous 365/24/7 monitoring. The ability to monitor autonomously, with remote diagnostics and remote relay which provide an alarm to the Fire Safety Officer or Facilities Manager, provides confidence in the integrity of the system. Minimising the risk of fire in the long run can improve business continuity. It also saves downtime and saves the potential costly pay-out which fire damage entails. Carl Hunter, having coined the term “the ungoverned space” as CEO of Coltraco Ultrasonics is proud to be at the forefront of the industry trend towards increased safety.

What methods are available now?

Ultrasonic technology holds the key. Coltraco Ultrasonics have developed a system capable of constant monitoring fire extinguishing cylinders with their Permalevel™ Multiplex. Currently, protecting similarly high value and critical infrastructure, such as electricity sub-stations, power generating stations and data centres, Permalevel™ Multiplex will provide the asset owner with complete 24/7 visibility of their system’s contents. This Safesite® solution enables mining sites to go above and beyond minimal regulatory compliance to develop their own best practice safety management system that may lead to better protection of asset and human life, as well as show their insurers their commitment to safety.

What is ultrasound?/p>

Ultrasound is merely sound beyond our audible range. Dolphins and whales can communicate at sea over long ranges as sound travels more efficiently through liquids than air. We use this principle to identify that difference in a cylinder containing liquefied agent. Consider ones ears as ”the receiver” and ones mouth as the “transmitter”. Sound will arrive at ones ears at different times. The reason though that we hear a unitary sound is that our brain processes it to one. This is what we do by processing the returning ultrasound. In the air bats navigate by airborne ultrasound. We can do the same for contents and room integrity monitoring in the fire industry.

By utilising a sensor which acts as a transceiver, an ultrasonic measuring device is capable of detecting liquid levels within any single-skinned container through transmitting an ultrasonic pulse and analysing the strength of the returned signal to determine the level of contents. As sound behaves differently in air and liquid, so will the strength of the returned signal be different in the liquid allowing us to identify the level of contents accurately. Similarly, leaks can be effectively detected through an ultrasound generator placed in an enclosure and an ultrasound receiver outside of the enclosure to measure the amount of ultrasound that leaks from the seals and cracks which has the potential to affect the ability for a clean agent to extinguish fires due to the retention time it needs upon discharge to function at its best. Taking these collected data and transmitting them wirelessly over TCP/IP, true remote monitoring of your fire suppression systems is possible anywhere around the world. 

Is bad engineering being rewarded?

Despite the technological advances in monitoring systems, the industry still approaches the installation of a dynamic and pressurised fixed gaseous extinguishing system as if it needs no integration into a Building Management System (BMS)/Safety Management System (SMS), except alerting on actuation. Nor does it think it needs constant monitoring, lest it reveals the underlying engineering risk of them. Can this be because good engineering is left unrewarded in fire safety matters? Or might it be that the fire industry is more concerned to negate customer awareness of its need lest it reveals that pressurised systems do discharge and leak? These are needless concerns. All good engineering demands the monitoring of dynamic structures and a highly pressurised cylinder is a dynamic structure. It is designed to protect a critical infrastructure or asset. Without constant monitoring a risk is generated in the very environment for which it is designed to reduce risk. The risk is not only to the asset, but to the people who work in the asset and their ability to enable business continuity in the high value asset under risk.

CASE STUDY: ultrasonic technology offers quick, safe & reliable solutions/p>

The importance of ultrasonic technology to the mining industry has been demonstrated by its use thus far. NRG Energy have been using the Portalevel™ Max since 2015 at the Morgan Town Generation Plant in Morgantown, Charles County in Maryland, US. The Morgan Town Plant is a coal powered power station based in Maryland. NRG own the USA’s largest and more diverse power generation competitive portfolio. NRG are dedicated to smart and reliable energy sourcing, and emission reductions although coal is a significant part of the electricity generation. The Portalevel™ Max is an example of the technologically advanced techniques that the company are implementing to lead the way in safe and sustainable coal sourcing.   After witnessing fire service experts undertaking ultrasonic liquid level indication in just minutes, they were keen to change from their previous method of weighing. As a safety critical asset, the Morgan Town Plant saw the necessity in investing into their fire safety. This was the same as at the Vales Point Power Station at Delta, Australia.  The power station is at the southern end of lake Macquarie. This power station was built in the 1960’s as a four-unit station, but now operates two 660 MW generating units. The Power Station is owned and operated by Power International, with the capacity of around 1,320 megawatts, providing 24 hours electricity. In 2013 they bought Coltraco Ultrasonics’ Portagauge® 3 thickness gauge for testing normal structure and stainless steel.

How to inspect liquefied gaseous systems with ease and speed/p>

Utilising ultrasound technology, Coltraco Ultrasonics have been manufacturing a range of ultrasonic portable liquid level indicators known as the Portalevel®. The Portalevel® MAX is the latest generation of the Portalevel® line and is designed to provide enhanced speed, operation and performance, especially for high intensity testing requirements and works brilliantly for testing cylinder contents of fixed fire extinguishing systems like CO2, NOVEC™ 1230, FM-200™ and other clean agents. The device has UL, RINA and ABS Type Approval, building further on their history of over 27 years manufacturing this equipment and showcasing the commitment to the marine and shipping industry. The Coltraco Safesite™ technology suite includes Portalevel ® MAX; a “world leading handheld ultrasonic liquid level indicator for testing most common extinguishing agents”; the Portasteele™ Calculator tablet based app converting the liquid level into agent weight/mass with ease, simplicity and ability to log the results; and the Permalevel ® Multiplex for 24/7, 365 autonomous, continuous monitoring of fire suppression systems, with remote relay, remote diagnostics and alarm capability to alert in case of agent leak/discharge.

How to constantly monitor liquefied gaseous extinguishing systems 24/7 /p>

Permalevel® Multiplex is the first system worldwide that is capable of monitoring the liquid level of critical fire suppression cylinder systems on a constant basis. It gives a facility total visibility on the real-time status of all their critical fire systems. Modern fire suppression systems have transformed industry safety across all sectors. However, the development of their servicing and monitoring equipment has remained stagnant, with many very advanced systems relying totally on annual inspections, or on unreliable mechanical pressure gauges. These methods leave the status of fire suppression systems completely vulnerable between annual checks. The Permalevel Multiplex® is designed to ensure that fire suppression systems are always fully operational and that no accidental discharge has occurred, which could affect the effectiveness of the overall fire protection system in the event that it is required for use 24/7 remote access to system status – enables the operator to monitor each cylinder point in real time. The ability to retrofit into existing systems which eliminates downtime as the system does not have to be disconnected/deactivated provides ease and simplicity to be installed across hundreds of cylinders present in a particular site.

How to test Room Integrity /p>

Where Portalevel® and Pemalevel® deals with the clean agent contents, Coltraco Ultrasonics has also designed and manufactured a device to monitor the enclosure integrity at which the clean agent discharges into. Prior to the installation of a clean agent extinguishing system, fire installers are required to determine the enclosure’s “hold time” in order to comply with regulations such as BS EN ISO 14520 and to ensure the enclosure is able to contain the released clean agent for a sufficient period of time in order to extinguish fires. This relies on the identification of leak sites within an enclosure and subsequently sealing them to improve the “hold time” when necessary. Coltraco Ultrasonics manufactures the Portascanner™ 520 which comprises of an ultrasound generator and ultrasound receiver whereby the ultrasound generator is left in an enclosure and the receiver is used to scan the enclosure seals to identify leak sites. This allows effective identification of leak sites and overall contribute to an increased reliability of a clean agent fire suppression system. A semi-permanent option is also available to monitor leak sites continuously, typically in old, grade listed buildings whereby protection from fire is of absolute importance.

Conclusion: Safesite® fire safety solutions

Coltraco Ultrasonics is a company that demonstrates their commitment to developing and supporting safety systems and test equipment with their customer and the end application in mind, founded on science and pursuit of mathematical justification such as their practice to precisely cite accuracy i.e. they achieve +/-1.5mm level of contents accuracy and identify leak sites as small as 0.06mm +/-0.02mm. This is a key contribution the company makes to the industry over their competitors, backed up by 30 years’ experience, operating in 108 countries and life-time customer care.

Request a Quotation

Online Submission

Click Here

Call: +44 207 629 8475

Our customer support line is open during UK
business hours
Mon-Friday, 9.00am - 5.00pm GMT

Email: sales@coltraco.co.uk

Enquire via email and a dedicated
member of the sales team will deal
with your request personally.

Cookies make it easier for us to provide you with our services. With the usage of our services you permit us to use cookies.