Oilfield noise mitigation

On a daily basis, offshore workers are exposed to an array of loud noises often for prolonged periods. Although the industry has in place strict guidelines with respect to the use of hearing protection, noise induced hearing loss remains a serious concern for the industry. Some 600 cases of hearing loss are reported annually to the Norwegian oil and gas industry alone and in 2016 the HSE estimated that 10 000 workers were exposed to noise above the Upper Exposure Action Values (UEAV) of 85 dB.

For an industry where noise remains a continuous problem for several reasons, this poses a significant threat to employee safety. The plant and equipment used for oil and gas production including high pressure pumps, compressors, and associated motors, turbines, pipes, valves and drill rigs, generate extremely high levels of noise and vibration. Add to this, the fact that such equipment is situated in close proximity to each other and the potential for workplace injuries and Noise Induced Hearing Loss (NIHL) in employees becomes even more prominent.

Prolonged exposure to excessive noise from such equipment can often lead to irreversible hearing damage and tinnitus, as well as more serious conditions such as permanent hearing loss (NIHL), cardiovascular diseases, sleep disturbance, stress, brain impairment and mental issues.

Whilst Personal Protective Equipment (PPE) is used to help to reduce hearing loss in oil and gas facilities key operators in the field are increasingly tackling noise at source and latest generation noise mitigation solutions are becoming increasingly popular in the oil and gas industry, particularly as the industry seeks to access new fields often in deeper waters. Such explorations require pumping equipment operating at higher pressures, creating even more difficult and noisy conditions in which to operate and increasing the health risks for employees.

Legislative limits

The issue is compounded by the increasingly strict regulations in the oil and gas sector, which call for the ongoing reduction in noise output, as well as the implementation of effective noise control measures on any oil and gas platform.

The fundamental legislation applicable to UK offshore installations is the Control of Noise at Work Regulations 2005, implemented under EU Directive 2003/10/EC and HSE publication OTR2001/068. This legislation imposes strict exposure limits within the sector and outlines technical recommendations for the way in which noise and vibration should be considered in the initial design stages of all infrastructure projects.

Under the Noise at Work Regulations, the upper and lower daily noise exposure action levels are 85 dB(A) and 80 dB (A) respectively. There is also an increased emphasis on controlling noise at source wherever possible, a sizeable shift from the focus of earlier legislation on assessment and quantification of exposure levels, and recommendations for hearing protection.

Consequently, pressure to find a solution to limit excessive noise and worker’s exposure to it has been growing for end users, with innovative industry leaders now offering customers tailor-made noise control solutions.

Noise control solutions

Many solutions are available, ranging from on-skid mounted localised acoustics enclosures, on-skid localised acoustic screening, as well as skid mounted and deck mounted fully encompassing acoustic enclosures.

Acoustic enclosure designs must cater for the inherent noise of the equipment and surrounding plant. The logistical and spatial limitations in terms or access to, from and around the rig also need to be reflected in the design of the packaged enclosure, along with consideration to all other health and safety factors.

Operators require these enclosures to be designed with the highest level of safety in mind. As such, factors such as accidental and environmental loads must be carefully considered in any noise mitigation solution.

In certain applications, for instance, blast loads must be carefully considered during the design and construction of acoustic enclosures. Through the process of design and utilisation of Finite Element Analysis (FEA) methods for both static and transient structural analysis, manufactured enclosures are intended to meet the specification requirements for the most onerous of blast load incidents.

Hazardous area compliance is also key for such noise control solutions. Depending upon the application, acoustic enclosures can include hazardous area complaint ventilation (ATEX) and filtration, full electrical fit-out terminated at internally or externally mounted junction boxes. Hazardous area lighting and emergency back-up lighting can also be specified; as well as fire and gas detection and suppression systems, which can comprise water mist or water deluge via an internally mounted pipework distribution.

To support plant access and maintenance requirements, acoustic enclosures can be designed and supplied with a wide variety of access and viewing options, including single and double leafed doors, hinged and sliding doors for personnel access, and various viewing options.

The correct design and selection of acoustic products in particular housings for plant items is essential. This must be achieved first time to avoid the serious implications of non-compliance of specifications and the excessively costly nature of retro fitting. There is no margin for error and with this in mind product performance should be tested to BS EN ISO 11546-1:2009, as required by BS EN ISO 15667 ‘Acoustics – guidelines for noise control by enclosures and cabins’.

With improved health and safety at the forefront of the offshore oil and gas industry and noise reduction becoming a major factor in this, the requirement of oil and gas companies to adopt noise control solutions beyond conventional personal protective equipment has never been more critical. Noise therefore will increasingly need to be addressed through the design and development of offshore platforms and associated equipment.

Wakefield Acoustics is a leading manufacturer and supplier of advanced industrial and environmental noise control systems to the offshore industry. With more than 35 years of experience of supplying bespoke industrial noise control solutions, the company has developed an extensive knowledge of high-specification NORSOK-compliant noise control solutions. These include bespoke blast rated acoustic enclosures with fire and gas detection and suppression systems, as well as electrical installations, along with a wide range of fully welded silencers and other ancillary equipment. For further information please visit: www.wakefieldacoustics.co.uk

Read the article online at: https://www.oilfieldtechnology.com/hse/16012017/oilfield-noise-mitigation/