Petroleum & Gas Inspectorate | Bulletin | No.18 V 1 | 28 February 2023

Noise Health Risk Assessment on drilling and completion operating plant and activities

What happened?

The Petroleum and Gas Inspectorate (PGI) has conducted Noise Health Risk Assessments (HRAs) across several operating plants to establish a baseline for hazardous noise. Noise-induced hearing loss (NIHL) is caused by exposure to loud noises over a period depending on the loudness, pitch, and length of time. NIHL is painless, progressive, permanent, and preventable.

How did it happen?

The Inspectorate conducted personal noise monitoring and area noise sampling in late 2022 to gather data across operating plant activities and provide thorough, qualitative evidence to assess the risk of hazardous noise via:

• 80 personnel wearing intrinsically safe dosimeters for their shift resulting in 78 personal noise reports
• 400 noise samples taken during 12-hour shifts across different operations within the work sites.

A detailed noise map and report was developed based on the samples collected and shared with the participants.

Key issues

• Drilling and Completion Operating Plant mobile heavy equipment were largely the source of the noise. This equipment was in operation continually for 12 hours to 24 hours and 85 per cent of the equipment surveyed registered average noise levels above the occupational exposure limits (OEL) as shown in Image 1.
• Drilling and Completions field personnel were monitored throughout a 12-hour shift with results compared against a threshold noise level of 82dB(A) OEL (shift adjusted).
• Existing noise assessment data from Operators:
• did not adequately assess personal noise exposure levels
• did not identify high noise exposure zones within the work sites
• did not benchmark noise sources against occupational exposure limits (OEL)
• included a combination of personal protective equipment (PPE), administrative and engineering controls for risk management. However, in some instances the engineering controls appeared to be ineffective, for example, doors left open on generator enclosures.
• PGI Noise HRA found personal noise levels recorded to be significantly more than the levels previously assessed by industry, with 90 per cent of participants exposed to noise levels above the shift adjusted OEL as shown in Image 2.
• NIHL is further compounded when there is exposure to physical (vibration) and Ototoxic chemicals such as carbon monoxide, organic solvents, mercury, lead etc.

Recommendations

• Review AS/NZS 1269.1:2005 Occupational Noise Management and conduct a gap analysis against existing assessments.
• Review current process to manage noise related risks to ensure workers are not exposed to noise levels exceeding OELs.
• The noise management plan or processes are to include:
  • a risk assessment to identify noise sources through testing by a competent person
  • review existing controls that manage noise exposure with a focus on:
    • controlling noise at the source or the receiver, for example, installing noise attenuating enclosures around engines and tailor the hearing protection to the noise hazard exposure of the worker
    • covering acoustically highly reflective surfaces such as metal with rubber matting and dampening resonance of machines which transfer energy through vibration.
    • controlling transmission path between source and receiver, for example, attenuating transmission through enclosures or barriers.
  • develop or include a worker health monitoring program with an audiometric testing as per AS/NZS 1269.4 to workers that are potentially exposed to noise limits exceeding the OEL
  • audiometric monitoring programs are mandatory for workers that are exposed to environments exceeding the following thresholds:
    • High noise exposure of L_{Aeq,8h ¹}100dB(A) or more; or
    • Ototoxic substances at any level and noise with L_Aeq,8h¹ greater than 80dB(A) or L_C,peak² greater than 135dB(C);
  • implement Hearing Protector Program (HPP) as per AS/NZS 1269.3 involving worker consultation, for example, fit testing of hearing protector devices (HPD)
  • develop and implement training program including information on noise hazards, impact to hearing when exposed to hazardous noise, and the selection, use, maintenance, and storage of HPD.

¹ L_Aeq,8h means the eight-hour equivalent continuous A-weighted sound pressure level in decibels (dB(A)) referenced to 20 micropascals; determined in accordance with AS/NZS 1269.1: Occupational noise management-Part 1: Measurement and assessment of noise emission and exposure.

² L_C,peak means the C-weighted peak sound pressure level in decibels (dB(C)) referenced to 20 micropascals; determined is accordance with AS/NZS 1269.1: Occupational noise management-Part 1: Measurement and assessment of noise emission and exposure.

References and further information

• Managing noise and preventing hearing loss at work Code of Practice 2021 (worksafe.qld.gov.au)
• AS/NZS 1269 Occupational noise management (set)