How to Calculate Site PPE Quantities
Required PPE quantity is calculated as: peak concurrent workers × number of shifts × 1.1 (10% spare). This ensures each shift has a full set of gear plus spares for damage or loss. Gloves are consumables — provide at least 2 pairs per worker. Fall arrest harnesses are sized to the number of workers doing elevated work at any one time.
OSHA requires employers to provide all required PPE at no cost to workers. Hard hats must meet ANSI/ISEA Z89.1 standards. Safety footwear must meet ASTM F2413. High-visibility vests should meet ANSI/ISEA 107 Class 2 or 3 for road or low-visibility conditions.
Establish a PPE inspection schedule: hard hats should be replaced after impact or every 5 years (2–3 years in UV-intensive environments). Harnesses must be taken out of service after any fall event or if visually damaged. Keep replacement stock on hand to avoid work stoppages.
Frequently Asked Questions
Workers may use their own PPE if the employer verifies it meets applicable OSHA and ANSI standards. The employer remains responsible for ensuring all PPE in use is compliant and properly maintained.
Replace hard hats after any impact or penetration, and at a maximum of 5 years from the date of manufacture. Suspension inserts should be replaced annually. UV damage and chemical exposure can reduce service life further.