KM - it is VERY common for risk assessments to default to the worst case consequence which is almost invariably at least one dead body per hazard/risk.
But some risks consistently produce more severe consequences and one of them is STAIRS.
Now even if the temporary handrails have not been removed for entirely justifiable reasons as set out in Roundtuit's response, imagine the headlines in the print any good story media.
Helpful workmate A is assisting injured person B down five flight of stairs using some evacuation equipment. Workperson C is climbing up the stairs carrying three lengths of wooden skirting, gets caught by the wind and the skirting swings round hits A who lets go of evacuation equipment and already injured B goes tumbling down the stairs and is killed or injured to a greater severity than before being moved.
Company Safety Manager explains that "We have 'Golden Rules' one of which is that anyone using stairs must hold on to a handrail at ALL times".
"Clearly, A could not possibly have held on to the handrail when moving the evacuation equipment and B wouldn't be able to either. Nobody consulted the Safety Department before agreeeing to the use of evacuation equipment to move a casualty".
"They could have easily moved the casualty using the hoist which was on site, with MUCH less risk."
Now in my earlier post I DID comment that what would be "reasonably practicable" would depend on the circumstances and decisions on what is or is not "reasonably practicable" should be adjudged on what the person doing the assessment should have known at the time - NOT with hindsight. It says so in the relevant case law.
No, suppose they are building a block of flats, the design may well include for the installation of one or more permanent passenger lifts and it might well be "reasonably practicable" to commission these relatively early in the construction programme (i.e. MUCH earlier than is often the case - "we didn't want to dirty the brand new lift, My Lud" - to which the retort might be "You could have provided protection to the internal surfaces of the lift").
BUT, we DON'T know the circumstances that the original poster refers to, so we cannot possibly tell what is or is not reasonably practicable without much more information.
However, we can conclude that using the goods lift is probably a much safer option than trying to maneouvre a casualty down the stairs using whatever standard evacuation equipment at a BUILDING SITE.
You might well say that person C shouldn't be carrying skirtings up the stairs but this sort of thing is just one of the many things that people do on stairs at a BUILDING SITE, however well managed, and it is just one of a 1000+ ways that might result in A and B not safely descending the stairs.
Now, if the safe working load of the goods lift is insufficient for the load of A + B plus some "plant" (within the meaning of HSWA) then it probably isn't fit for the purpose it has been installed - to lift and lower much heavier loads.
I've been pushed down stairs (as the guinea pig to let a trainer user put their training into practice) in an Evac Chair when a fire alarm has sounded.
One of the things I could be reasonably confident about would be that there would be nobody climbing UP the stairs carrying anything such as to present risk to me B or A helping me down.
Whenever deciding what is reasonably practicable you have to consider the NEW risks that whatever mitigation is being thought about will introduce into the equation.