There are such documents which are used in industry - Dynamic Risk Assessments, also known by other terms. I have seen them in practice and their use is limited in my opinion. There is generally too much reliance on paper work. That said, for high risk work like working at height I think DRAs can be useful as an aid memoir when the hazards associated with the working environment may not be known in advance.

For reactive maintenance you could use a generic suite of documents which should provide cover for most types of maintenance, certainly the more significant risks, such as, electrical, asbestos, W@H, etc. Personally I think providing some meaninful training to operatives and supervisors would be more beneficial than a piece of paper by empowering people to make informed decisions.

If the risks are non-trivial wouldn't these non-routine activities come under the PTW system? Whereby a suitable JSA should be prepared for the task to accompany the permit?

If you are dealing with process plant or rotating equipment this should be mandatory, despite the urgency of the maintenance request.

I always get uneasy when I find people wanting to place total reliance on DRA approaches to risk assessment. In reality they can only be an adjunct to a properly formulated set of risk assessments. Although I know they ae used differently.

It is perfectly feasible to set up some form of risk assessments for the range of tasks for which the operatives are trained to be involved and then use DRA to check that risks are fully controlled and then finalise the RA to create a task risk assessment for the work. DRA is then used subsequently during the task as a form of feedback loop reassessing continuously that what is expected is happening, if not reassess the risks. Over time it is perfectly possible to build up a significant range of task risk assessments to use as the basis for future work.