NEBOSH CC Dust & Noise in Construction 4 — Questions and Answers
Question 1: What health surveillance is required for workers regularly exposed to noise at or above the upper action value?
- Regular audiometric testing (hearing tests) to detect early hearing loss (Correct answer)
- Annual chest X-ray
- Blood pressure monitoring
- Lung function tests
Correct answer: Regular audiometric testing (hearing tests) to detect early hearing loss
Workers regularly exposed to noise at or above the upper action value must be offered regular audiometric testing (hearing tests). This detects early signs of hearing damage, allowing control measures to be adjusted before significant harm occurs.
Question 2: What is the SNR (Single Number Rating) of hearing protection and why is it important?
- It indicates the average sound attenuation provided across frequencies; used to select appropriate protection for the noise level (Correct answer)
- It is the maximum noise level the protection is designed for
- It rates the comfort of hearing protection
- It identifies the frequency of sound the protection is designed to block
Correct answer: It indicates the average sound attenuation provided across frequencies; used to select appropriate protection for the noise level
The SNR is a simplified method for estimating the noise attenuation provided by hearing protection. It is used to select protection of sufficient attenuation to bring the exposure at the ear below the exposure limit value.
Question 3: What type of hearing protection provides the highest level of attenuation?
- Ear defenders (muffs) combined with ear plugs for very high noise levels (Correct answer)
- Ear plugs alone
- Disposable foam ear plugs only
- Custom-moulded ear plugs
Correct answer: Ear defenders (muffs) combined with ear plugs for very high noise levels
For very high noise levels, wearing both ear defenders (muffs) over ear plugs provides the greatest combined attenuation. However, the combined SNR is not simply the sum of both — typically adding about 5 dB to the higher-rated device.
Question 4: What is 'hand-arm vibration' (HAV) and which construction activities generate it?
- Vibration transmitted from vibrating tools to the hands and arms; generated by grinding, drilling, breaking and compacting (Correct answer)
- Vibration of the whole body from sitting on machinery
- Vibration from walking on vibrating surfaces
- Vibration from manual handling of heavy loads
Correct answer: Vibration transmitted from vibrating tools to the hands and arms; generated by grinding, drilling, breaking and compacting
Hand-arm vibration is mechanical vibration transmitted from vibrating tools and machinery to the hands and arms. It is generated by power tools such as angle grinders, hammer drills, jackhammers and vibrating compactors.
Question 5: What is the COSHH assessment for dust used for?
- To identify hazardous dusts, assess exposure levels and determine appropriate control measures (Correct answer)
- To record all dust-related illnesses on site
- To set the dust suppression schedule
- To provide a list of dust types found on the site
Correct answer: To identify hazardous dusts, assess exposure levels and determine appropriate control measures
A COSHH assessment for dust identifies the types of dust generated, assesses how much workers are exposed to (compared with WELs), determines whether exposure is adequately controlled, and specifies control measures to protect workers' health.
Question 6: What is the correct fit test for a tight-fitting respirator (FFP mask) called?
- Fit testing (Correct answer)
- Face seal check
- Mask trial
- Fit checking
Correct answer: Fit testing
Fit testing is the formal procedure to verify that a tight-fitting respirator provides an adequate seal to the wearer's face. There are two types: qualitative (using a substance the wearer can smell or taste if it leaks) and quantitative (using instruments to measure leakage).
NEBOSH CC Dust & Noise in Construction 4
What health surveillance is required for workers regularly exposed to noise at or above the upper action value?