Brunette Girl On The Old Wooden Chair

The Business and Institutional Furniture Manufacturer's Association (BIFMA) defines BIFMA X5.1 for testing of commercial-grade chairs. It specifies things like:
• chair back strength of 150 pounds (68 kg)
• chair stability if weight is transferred completely to the front or back legs
• leg strength of 75 pounds (34 kg) applied one inch (25 mm) from the bottom of the leg