I believe the 9m rule is for vertical, fixed ladders like on tower crane access or escape routes.
I used to use the 40ft triple extension many times in the past but if an accident occurs, you might have to justify why collective prevention wasn't used instead.
This was a question asked on the HSE communities page.
QUESTION:
Are there any specific height restrictions where the use of a ladder or step ladder, as a piece of access equipment, is not permitted?
ANSWER:
The law does not state heights but clearly the selection of the most appropriate access equipment for a particular task is a requirement of the law.
You also have a duty, where working at height cannot be avoided, to take suitable and sufficient measures to prevent, so far as is reasonably practicable , any person falling a distance liable to cause personal injury.
Work platforms, scaffolding, towers, all offer protection from a fall occurring. Ladders and step ladders do not offer fall protection, so should be the last form of work access equipment to be considered.
If you have selected ladder use, your risk assessment must justify why safer equipment is not possible to be used.
If your risk assessment determines that a ladder is the right piece of equipment to be used , then the right ladder should be selected and used in the correct manner.
Ladders should be used for low risk and short duration tasks, and three points of contact should always be maintained to prevent a person slipping and falling.
The risk of falling onto something below a ladder (e.g. spiked railings or glass covering) is equally relevant in terms of risk as the height of the potential drop. Our web page has both the :
Work at Height Regulations 2005
http://www.hse.gov.uk/falls/regulations.htm and:
Guidance on the safe use of ladders and step ladders at
http://www.hse.gov.uk/falls/ladders.htmHope that helps.