12.4.8 Castors and Wheels
Castor wheels may be metallic, non-metallic, tyred, swivel or fixed to suit various site conditions. Two classes of castors are generally used:
Light duty - These are suitable for carrying the weight of the mobile supporting structure only but are NOT capable of taking the weight of the load. Light duty castors must always be used in conjunction with jacks.
Medium duty - These are suitable for carrying the weight of the mobile supporting structure and, when static, sustaining the weight of the load. Medium duty castors may be provided with brakes and/or rotational locking devices to prevent accidental movement of the structure when lifting.
Heavy duty castors are not generally used for standard mobile supporting structure. They may be used for special purposes, such as movement under load and are therefore outside the scope of this section of the code.
A supporting structure without castors or wheels can still be considered to be mobile if it is designed to be free standing and be easily dismantled or moved.