Legal and management framework, including CDM duties and roles
The legal ladder
Start with the Health and Safety at Work etc. Act 1974: section 2 (employers to employees), 3 (others affected), 4 (premises), 6 (articles and substances), 7 (employees' own duties) and 37 (offences by directors where consent, connivance or neglect is proved). Below it sit the Management of Health and Safety at Work Regulations 1999 - the universal duties of risk assessment, competent assistance, arrangements, cooperation, information and training - and the Construction (Design and Management) Regulations 2015, which apply to every construction project in Great Britain, domestic or commercial, with no minimum size.
CDM duty holders
The client is the person the project is carried out for and carries the most duties: make suitable arrangements, provide pre-construction information, ensure a construction phase plan exists before work begins, ensure a health and safety file, and ensure welfare. The principal designer plans, manages and monitors the pre-construction phase; the principal contractor does the same for construction and must ensure inductions, supervision and welfare. Designers must eliminate or reduce risk in the design. Contractors and workers have their own, non-overlapping duties.
Traps: the construction phase plan is needed on all projects, not only notifiable ones; a principal designer and principal contractor are appointed in writing and are required only where more than one contractor is involved (otherwise those duties fall to the client); the health and safety file is needed only where more than one contractor is involved; the client cannot simply transfer duties to the contractor.
Rule of thumb: an F10 notification is required only where the project will last more than 30 working days with more than 20 workers simultaneously on site at some point, or exceeds 500 person-days.
Worked example: a six-week refurbishment with eight workers - 30 working days and 210 person-days. Neither trigger is met, so no F10 - but the construction phase plan, welfare and inductions are still mandatory.