Businesses in the industrial door sector supply, install, maintain and repair doors and access systems for commercial, industrial and public buildings. Their work may cover roller shutters, sectional overhead doors, rapid-action doors, fire doors, loading-bay equipment, gates and vehicle barriers. They can advise on suitable door types, dimensions, materials, insulation and operating mechanisms for a building or site. Services commonly include site surveys, installation, safety checks, repairs and planned maintenance. Engineers may work on motors, controls, sensors and other automated components, as well as manual doors and their fittings. Some businesses also provide replacement parts, emergency repairs and servicing intended to keep equipment operating safely and reliably. The exact range of products and services varies, and may be focused on particular door systems or customer sectors.