CourseWiki/Safety/Universal Rules

Personal Protective Equipment

What you wear, and when. Eye protection is mandatory in the lab spaces at all times; the rest depends on the task.

Five topics. One of them — eye protection — applies the moment you walk in. The rest are set by what you are doing.

Eyes: Always, in the lab spaces. No exceptions.
Hearing: Prolonged exposure to loud equipment.
Feet: Closed-toe shoes, always.
Respiratory: Any grinding or sanding; hazardous dust or fumes.
Clothing & hair: Always, near anything that rotates.

Eye protection; Watch out

Eye protection

Safety glasses are MANDATORY in the lab spaces at all times.

If you wear prescription glasses

Side shields that attach to your existing frames.
Oversized safety glasses that fit over corrective glasses.
Prescription safety glasses are also acceptable.

Lens requirements

Safety glasses must be clear or yellow tinted only.
Dark or shaded safety glasses are not acceptable for indoor lab use.
Must meet ANSI Z87.1 safety standards.

Hearing protection; Watch out

Hearing protection

Industry standard: shop tools nearly always require hearing protection in professional settings. In a teaching lab the exposure is typically shorter than in production work, but the protection still matters.

When to use it

Required for prolonged exposure to loud equipment — grinders, sanders, planers and similar.

The rule of thumb: if you have to raise your voice to be heard by someone at arm’s length, it is loud enough to need protection. You do not need a meter, and most shop tools fail this test the moment they start.

The numbers behind it

OSHA measures noise as an average across the working day, in A-weighted decibels (dBA). Two figures matter:

85 dBA: The action level, averaged over 8 hours — the point at which a workplace must run a hearing conservation programme.
90 dBA: The permissible exposure limit, averaged over 8 hours.

Above 90 dBA the allowed time drops fast — every extra 5 dBA halves it:

90 dBA: 8 hours
95 dBA: 4 hours
100 dBA: 2 hours
105 dBA: 1 hour
110 dBA: 30 minutes
115 dBA: 15 minutes or less

Impact noise should not exceed 140 dB peak — a single hammer blow or nail gun can reach it, and that damage is immediate rather than cumulative.

These are OSHA workplace limits (29 CFR 1910.95). NIOSH recommends a stricter 85 dBA limit that halves the allowed time every 3 dBA rather than every 5. Hearing loss from noise does not come back, so treat these as ceilings, not targets.

Two types available

Earplugs: Small foam plugs inserted into the ear canal. Disposable or reusable. Available on request from the instructor.
Ear muffs: Over-ear cups covering the whole ear. Reusable and adjustable. Often preferred for intermittent use.

Both types significantly reduce harmful noise levels.

Foot protection

Minimum requirement: closed-toe shoes are MANDATORY — no sandals, no flip-flops, no open-toe footwear.

Recommended upgrades

Slip-resistant soles, for traction on surfaces that may be slippery.
Puncture-resistant soles, against sharp metal debris.
Steel-toe or composite-toe protection — recommended, not required.

Avoid

Canvas shoes or thin-soled footwear.
High heels or unstable footwear.
Anything that does not fully enclose your feet.

You will be standing for most of the lab period — choose something supportive and comfortable.

Respiratory protection; Stop

Respiratory protection

MANDATORY when using any grinder or sander, and when working with materials that produce hazardous dust.

Grinding galvanized material is PROHIBITED. Zinc fumes from galvanized steel are toxic when heated.

Health hazards

Metal dust and particles cause respiratory irritation and long-term lung damage.
Wood dust can cause allergic reactions.

Dust and fumes are not the same problem, and they do not take the same protection. The next section is the one that decides which you need.

Respiratory protection — what to wear; Stop; Watch out

Respiratory protection — what to wear

A dust mask does nothing against fumes or vapours. An N95 is a particle filter. It does not stop gases, welding or brazing fume, solvent vapour, or anything else you can smell. Wearing one while you can smell the air is not protection.

For dust — grinding, sanding, sawing

N95 mask: Filters 95% of airborne particles. The minimum for dusty work.
Half- or full-face respirator: Fitted with a particulate filter, for heavy or extended dust.

For fumes and vapours

You need an approved respirator with the right chemical cartridge, not a dust mask. Ask the instructor which cartridge before you start.
A respirator only works if it seals. A loose mask, or a beard along the seal, defeats it.
If there is no correct cartridge available, the job does not happen until there is.

If you can smell fumes or taste particles, your protection is inadequate. Stop work immediately and upgrade it — or stop the job.

Chemicals and liquids carry their own handling and first-aid information — see Chemicals and Safety Data Sheets.

Clothing and jewelry; Stop

Clothing and jewelry

Loose clothing and accessories catch in rotating machinery. That is how this causes serious injury or death — it is not a dress code.

Prohibited

Loose-fitting clothing, or garments with dangling features — drawstrings, ties and similar.
Long sleeves, hoodies or jackets near rotating equipment.
ALL jewelry, except silicone wedding rings.
Neckties, scarves and lanyards.

Hair, and what to wear instead

Hair

Long hair must be secured back and kept away from equipment.
Use hair ties, clips or caps to prevent entanglement.