Safety


35


columns, scrubbers, reaction vessels and piping are obstructing the line of sight the open path system is unlikely to have the ideal surroundings to operate to its full potential. For a location that has been assessed as a high-risk leak area during a HAZOP study, such as a gas compressor or volatile liquid pump, a fi xed location gas detector may be more suitable.


Given the differences that exist, is there a right or wrong gas detection system? Or is it the case that each has its purpose and a combination of strategies is the most effective solution? To investigate the consensus on the most suitable applications for fi xed gas detection systems, portable gas detection systems and open path gas detection systems several leading equipment suppliers and systems integrators in the sector were invited to participate in a short questionnaire. Six companies chose to participate and the average their responses is presented here.


Digital innovation potential


All these gas detection systems lend themselves to the increased use of wireless communications technology allowing easer installation and more effective communications. Units can be set up to act as one large mesh network and some may be selected as communications gateways. Additionally, for portable gas detectors, peer notifi cation of alarms combined with remote monitoring allows for shortened response time, plus


accountability of users. They also enable voice communications or “man-down” communication from the user to a base location.


Digital innovations also have the potential to minimise the short-comings of some of the systems. For example, increased diagnostics and intelligence can minimise the frequency of false- alarms caused by rogue readings on chemical sensors or physical obstructions such as birds or trucks passing through an open path gas detector beam.


A cocktail of solutions


In summary, each system has its strengths. For example, a portable gas detector is just right for short term entry into a confi ned space such as a reactor vessel that requires inspection. It is also ideal for use in areas that will be temporarily occupied such as gas exploration drilling rigs or construction sites. On the other hand, a fi xed gas detector, for example sniffi ng for hydrogen sulphide close to a fl anged joint on a Claus desulphurisation reactor would be ideal for integration into the site alarm network. And, an open path system is a great option for monitoring the perimeter of the process fi eld to detect a hydrocarbon gas cloud that may be moving towards the administration building or control room.


It is also the case that each system has its limitations. Fixed and portable chemical-based gas detection systems require frequent


bump testing and periodic calibration – and that incurs some ongoing maintenance effort and cost. Portable systems are not easily integrated into site alarm systems and the battery will require periodic re-charging, making them unsuitable for long term use away from a charging station. Open path systems can have comparatively high one-time installation costs and are limited in the number of toxic gases that they can detect. Despite their comparatively high cost per system, due to their large range a single pair of open path optical gas detectors may be able to do the job of many fi xed chemical detectors and the maths can quickly add up to cost savings.


Rather than pick a single system, most refi nery and hydrocarbon processing sites will fi nd it optimal to employ a cocktail of solutions. Portable devices for site-walks and the release of confi ned spaces to issue a permit to work for maintenance. Fixed systems for leak detection around high risk equipment and integration to the site alarm system. Open path systems for large zone coverage and to validate the alarm signals generated by other fi xed gas detection systems. As with many aspects of health, safety and environmental management it’s not a black and white question of either / or but a more colourful rainbow of solutions that will lead to the optimal protection of people, assets and sites.


With thanks to: Almont do Brasil, Clean Environment Brasil, DCT-Multitech Consultoria Treinamentos e Serviços, Gastech Australia, JDuarteG Consultoria, R2 Safety, United Electric Controls


Picture credit: ALTAIR 4X - MSA


Author Contact Details Stephen B. Harrison, Principal, Germany at Nexant • Kranzlstraße 21, 82538 Geretsried, Germany • Tel: +49 (0)8171 24 64 954 • Email: sbharrison@nexant.com • Web: www.nexant.com


Do you have an article for Petro Industry News? If so please contact Helen Jones today.


helen@pin-pub.com OCTOBER / NOVEMBER • 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