Sulphuric Acid Drain Cleaners
COSHH assessment
A COSHH assessment for sulphuric acid drain cleaners on a UK construction site: what it does to people, how it gets into them, the controls that stop it, the PPE for what is left, and what to do when it goes wrong. Copy it into your assessment and change what does not fit your job.
Hazards to health
Concentrated sulphuric acid (often >90%), severe chemical burns, exothermic with water (splash hazard), reacts with metals to produce hydrogen, reacts with bleach to produce chlorine gas.
Routes of exposure
Skin contact, Eye contact, Inhalation (mist/fume)
Control measures
- Eliminate where alternatives exist (sodium hydroxide, enzyme drain cleaner, mechanical rodding).
- If used: pour slowly down empty drain, never into standing water (steam-acid splash).
- Sodium bicarbonate neutraliser on hand.
- No mixing with bleach or other cleaners.
PPE for what is left
- Butyl gauntlets, Full face shield, Acid apron, Wellington boots, A1B1 cartridge respirator if poorly ventilated
Emergency procedures
- Skin: irrigate 20 minutes minimum, urgent A&E.
- Eyes: irrigate 20 minutes minimum, urgent 999/A&E.
- Inhalation: fresh air, 999.
Questions people ask
Do I need a COSHH assessment for sulphuric acid drain cleaners?
If the substance is hazardous to health and your work exposes people to it, yes. The Control of Substances Hazardous to Health Regulations 2002, regulation 6, require a suitable and sufficient assessment before the work starts, with the significant findings recorded if you employ five or more. The safety data sheet is an input to the assessment, not a substitute for it. Guidance, not legal advice.
What is the difference between a safety data sheet and a COSHH assessment?
The data sheet is the manufacturer describing the product in general. The assessment is you describing how your people use it on your job: how much, how often, for how long, in what ventilation, with what controls. Two firms using the same tin can have very different assessments.
What is a WEL?
A Workplace Exposure Limit, the maximum airborne concentration averaged over a reference period, set in HSE document EH40. Where one applies to this substance it is stated in the hazards above; where it does not, the duty to reduce exposure so far as is reasonably practicable still stands.
Is PPE enough?
No. COSHH puts PPE last: eliminate the substance, substitute for something less harmful, control at source with ventilation and enclosure, then organise the work to reduce exposure, and only then PPE for what is left. An assessment that jumps straight to gloves and a mask is the kind an inspector questions. Guidance, not legal advice.
How often should it be reviewed?
When the product, the method, the quantities or the people change, if there is any sign the controls are not working, and at least every year or so regardless. Health surveillance may be required where exposure could cause an identifiable disease, such as dermatitis or occupational asthma.
The COSHH assessment writes itself
Pick the substance in the SiteLynx RAMS editor and the COSHH assessment fills in with the hazards, controls and PPE, alongside the HAVS and noise assessments for the tools you chose. Signed on site on a phone. 14 days free.
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