Diptone

Consultancy

 Design and Assessment of Hydrometric Cableway Systems

Whether under the Provision and Use of Work Equipment Regulations (PUWER) or the Lifting Operations and Lifting Equipment Regulations (LOLER) it is necessary to ensure that stream gauging cableways are fit for purpose and safe to use.

Because a load is involved in the form of the sinker weight, current opinion is that the lifting regulations apply although, because the operation takes place over a river or stream, the risk to the operator or the public from a falling load is small.  Accidental overloading is a greater risk during flood gauging, when floating debris can become attached to the sounding cable.

However, it is important to remember that the purpose of an installation is to deploy a current meter rather than to lift ad hoc loads.  For this reason, the criteria for specifying the working sag are different from those that may be applied to a cableway designed for transporting material.

For “normal working” it is appropriate that the factors of safety and coefficients of utilisation required for lifting equipment apply to ropes and fittings.  It is also important to protect against conditions, which can arise during river gauging but are not “normal working”.  General design guidance, including factors of safety for the various components is provided by BS ISO 4375:2000, “Cableway systems for stream gauging”.  This standard supersedes BS 3680 Part 8D 1980.

Our equipment design and inspection procedures are based on ISO 4375:2000, the Code of Practice for the Safe Use of Lifting Equipment (COPSULE) and the requirements of LOLER.

Many existing cableways installed 30 or 40 years ago were poorly designed or have no records showing their construction.  To deal with these we have developed load limiting devices to protect the bank-side structures