Safety Gas Safety in Confined Spaces


A confined space is any space large enough for someone to enter and perform assigned work, which has limited means of entry or exit, and which is not designed for continuous worker occupancy. This covers just about every industry, including utilities, construction, hydrocarbon exploration and processing, petrochemicals, marine, agriculture, food processing and brewing, as well as the emergency services.


Employers must assess the risks these workplaces pose to their employees and endeavour to prevent them. In most cases, both the assessment and the safe working system will require testing of the atmosphere with gas detection equipment.


Crowcon’s (UK) Gas-Pro multi-gas detector is ideal for this purpose. Robust, reliable and simple to use with a bright, easy to read display and long battery life, it means personnel entering confined spaces can focus on the task in hand, safe in the knowledge that their gas detector is watching their back.


Confined space gas risks can be divided into three broad categories: combustible gas, toxic gas, and oxygen depletion or enrichment.


Combustible gas risks; For combustion to occur the air must contain a minimum concentration of combustible gas or vapour. This quantity is called the lower explosive limit (LEL). Different compounds have different LELs so it’s vital that detectors are capable of detecting at the correct levels.


Typically, storage vessels which have contained hydrocarbon fuels and oils present a danger. Other dangers come from fuel leaks: burst fuel containers; pipelines on and off site, gas cylinders and engine-driven plant. For workers in pits, sewers and other sub-surface locations, methane formed by decaying organic matter is an almost universal danger.


Toxic gases and vapours; Confined-space workers may be exposed to many toxic compounds, depending on the nature of the work. A risk assessment should be made of which toxic substances a worker may be exposed to in any given work situation.


When looking at toxic gases related to specific applications, the water industry for example uses many toxic compounds for cleaning and processing both waste and clean water. Hazards such as chlorine, ozone, sulphur dioxide and chlorine dioxide then pose additional risks both in storage and treatment areas. Oxygen - too high or too low?; The normal concentration of oxygen in fresh air is 20.9%. An atmosphere is hazardous if the concentration drops below 19.5% or goes above 23.5%.


Without adequate ventilation, the simple act of breathing will cause oxygen levels to fall surprisingly quickly. Combustion also uses up oxygen, so engine-driven plant and naked flames such as welding torches are potential hazards. Oxygen can also be displaced. Nitrogen, for example, when used to purge hydrocarbon storage vessels prior to re-use, drives oxygen out of the container and leaves it highly dangerous until thoroughly ventilated.


High oxygen levels are also dangerous. As with too little, too much will impair the victim's ability to think clearly and act sensibly. Moreover, oxygen-enriched atmospheres represent a severe fire hazard.


Both portable and fixed gas detectors can be used for confined space monitoring. Fixed systems typically comprise one or more detector "heads" connected to a separate control panel. If a detector reads a dangerous gas level, the panel raises the alarm by triggering external sirens and beacons. This sort of installation is suited to larger spaces like plant rooms, which have sufficient room for the hardware or remote stations that are usually unmanned.


However, much confined space work takes place in more restricted areas, making compact portable units more suitable. Ease of use, with one button operation, means minimal training is required while increased safety is ensured. Combining one or more sensors with powerful audible and visual signals to warn when pre-set gas levels are reached, portable detectors can be carried or worn wherever they are needed. In addition, a compact instrument is easily carried in a confined space, ensuring that pockets of high gas concentration are not missed.


Certain features should be expected in every portable gas detector. Clearly, life-saving tools for demanding environments must be as tough as possible, with reliable electronics housed in impact-resistant casings. While the need to leave gas sensors exposed to the atmosphere means that no instrument can be fully sealed, a high degree of protection against dust and water ingress is essential. Toughness notwithstanding, a well-designed detector will also be light and compact enough to wear for an entire shift.


Finally, because of the difficulties of working in a cramped space, perhaps under poor lighting, instruments should be easy to use. No matter how advanced a detector's internal architecture or data management options, personnel in the field should be faced with nothing more daunting than a clear display, simple, one-button operation and loud/bright alarms.


Reader Reply Card No 35


Filter Selection Made Easy Free Online Filter Selection Tool


With hundreds of different filters available for respiratory equipment, choosing the right one for your environment can be tricky. If incorrect, the wrong filter can put your employees at severe risk. Scott Safety (USA), specialists in respiratory protection, have launched the SureLife Filter Calculator, an online tool that recommends the most suitable filter based on the user’s data.


Mark Andrews, Air Purifying Product Manager at Scott Safety, explained, “We’ve introduced the SureLife Filter Calculator as a way to help simplify filter selection and to ensure you’re getting the appropriate level of protection. The free online tool allows users to input their own data to select an appropriate filter for their specific environment. The calculator has a comprehensive database of respiratory hazard data to make an appropriate filter selection for specific hazard environment and recommends compatible equipment to ensure the user has all information required for adequate protection. Importantly, the tool also indicates where filter- based respiratory products are not suitable, for example where breathing apparatus is required in oxygen-deficient atmospheres.


The product selector guides the user through the suitability of work environments, the types of dusts, fumes or mists present and the contaminants likely to be encountered. The calculator then allows the user to select input exposure limits before it identifies what type of filter should be used. The software is inherently sophisticated to use additive toxicity rules so filter recommendations can even be made for hazard mixtures, which can often be experienced in real-life situations.


The SureLife Filter Calculator is an ideal way of getting a quick, simple but accurate filter recommendation for air purifying respirators and should be used as part of an existing respiratory program.


Reader Reply Card No 36 Standalone Gas Detection Device


SY2 from GEIT (Italy) is a standalone device, detection for flammable gases, toxic gases, CO2 and oxygen. Certified to: II 2 G Ex d IIC T6 ( Ta - 50°C. + 80°C ), II 2 D Ex tb IIIC T85°C. Ta - 50°C + 80°C.


This makes it particularly suited to the demanding conditions encountered in the chemical and petrochemical industry on & off shore. SY2 can be supplied in different electronic configurations: B (Base): Only 4 - 20 mA signal output and calibration via IrDA interface and external Hand Held Programming unit; B/D (Base + Display); B/D/R (Base + Display + Relay); B/D/R/SL (Base + Display + Relay + Se-rial Link); Optional SIL 2 certified conbinations


Reader Reply Card No 37


New White Paper on DualSense Technology


A new white paper, “DualSense Technology: Why two are safer than one,” has been released by Industrial Scientific (USA). It is a resource for those who want to learn more about DualSense Technology found in the company’s newest single gas monitor – the Tango TX1.


The white paper reveals statistics on the low frequency of gas detector


bump tests being performed, and the risks workers take by using an instrument that has not been proven fully functional and reliable via a bump test. This data, derived from a study of more than 25,000 gas monitors used in the field and more than 2 million bump tests, prompted the development of the redundant sensor technology.


DualSense Technology includes two of the same type sensor for the detection of a single gas. The two sensor readings are processed through a proprietary algorithm and displayed as a single reading to the user. With Tango’s DualSense Technology, workers are safer regardless of bump test frequency.


“On average, workers using an instrument with DualSense Technology are 85 times safer than those using a typical single gas monitor,” said Raghu Arunachalam, Ph.D., global director at Industrial Scientific and author of the white paper. “DualSense Technology is a cost-effective way to significantly improve the safety of all workers protected by single gas monitors.”


Reader Reply Card No 38


13


APRIL / MAY 2013 • WWW.PETRO-ONLINE.COM


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52