Measuring the noise attenuation of shotblasting helmets

Area of Science:

• Occupational Health and Safety
• Acoustic Engineering
• Personal Protective Equipment

Background:

• Abrasive blasting operations require air-fed helmets for protection.
• BS EN 271:1995 covers helmet construction and air supply noise but lacks noise attenuation requirements.
• High noise levels from blasting processes pose a risk to users.

Purpose of the Study:

• To develop a standardized test method for measuring the noise attenuation of shotblasting helmets.
• To provide manufacturers with a means to objectively report helmet performance against blasting noise.
• To inform the revision of BS EN 271:1995 regarding noise attenuation standards.

Main Methods:

• Development of an objective test method utilizing a head and torso simulator (HATS).
• Measurement of noise attenuation using the HATS with typical shotblasting noise.
• Comparison of HATS results with measurements from human subjects.
• Assessment of HATS for measuring air supply noise as per BS EN 271:1995.

Main Results:

• The developed HATS-based method accurately measures shotblasting helmet noise attenuation.
• Attenuation values obtained using HATS correlate well with human subject measurements.
• The same HATS can be used for measuring air supply noise, replacing human subjects.
• The current standard (BS EN 271:1995) has a significant omission regarding noise attenuation reporting.

Conclusions:

• A viable objective test method using HATS for measuring shotblasting helmet noise attenuation has been established.
• The HATS, already used for compliance, can be leveraged for noise attenuation assessment.
• The findings support the inclusion of noise attenuation measurement and reporting requirements in future revisions of BS EN 271.