As a new user of this forum, I think it's great; so many different view points and from different areas can do nothing but educate and inform us all.
From the replies I've read on this issue and I whole heartedly agree; the use of a park brake to adjust a load is impractical in the real world and I find it hard to accept that any legislative body would incorporate this in any regulation.
I've been in this business for almost 30 years and have never seen an operator use a park brake when adjusting a load. It just doesn't make sense in the real world to expect this will be done.
Having said that, I need (as some of you already have), to draw the distinction between a sit-down rider type counter-balanced truck and a stand-up rider narrow aisle truck.
We're talking about sit-down counterbalanced trucks here.
Most internal combustion trucks have an inch or creep pedal (not a clutch) for ergonomics for the driver. In order to elevate a load, we need some RPM on the engine so our right foot needs to be on the gas pedal. Our left foot can be on the inching or creeper pedal which is also a brake. A driver does not need to put a truck into neutral in order to rev the engine, they just use the inch/creep/brake pedal.
On electrics, the lift travel speed is dictated by how far we pull the lever back so no need to keep our foot on the accelerator; we step on the brake.
Many operators' manuals and regulations state to park on a flat/level surface. A park brake cannot be trusted 100% and many trucks being used out there have parking brakes that are not adequate to hold a lift truck.
If for some reason, a person was elevating a load on a slope/grade I would question if we should be doing this, but in the event this happens, sure, using a park brake as well can be an added safety precaution to prevent inadvertant movement of the lift truck.
Some lift truck manufacturers have removed the inch/creep/brake pedal and incorporated a much wider brake pedal so an operator's left foot can be used on the service brake pedal for inching/creeping and elevating a load.