If you are appointing a scaffold contractor to work on a project you must take reasonable steps to ensure that the contractor undertaking the work has the necessary skills, knowledge, experience and capability to carry out the work in a way that secures health and safety. What is deemed reasonable steps will depend upon the complexity of the project and the range and nature of the risks involved.
You should ensure that the contractor has the appropriate systems and policies in place to set acceptable health and safety standards which comply with the law, and the resources and staff to ensure the standards are delivered onsite. Sensible enquiries should be made about their capability to carry out the work, excessive or duplicated paperwork should be avioded because it can distract from the practical management of risks. Where you are appointing a scaffold contractor you may find the PAS91 document useful, it offers guidance which will help you assess a contractors' capabilty.
As well as carrying out pre-qualification checks on contractors, you should also be looking to ensure that they have suitable experience and a good record in managing the risks involved in similar projects. Due weight should also be given to contractors who maintain membership of an established institution or body. Membership organisations, like ourselves, have arrangements in place that provide reassurance to clients that they are engaging suitable and capable contractors.
You must be able to demonstrate that you have the sufficient skills, knowledge, and experience to carry out the work you are being engaged for, and that you are keeping these capabilities up to date.