Zone and protection
Chemical plants can have different risk zones under the same roof. The classification of the zone the crane will work in, and the group of substances present, determine the required protection level. This information is in the facility's explosion protection document.
In areas with corrosive vapour, even without an Ex requirement, material and paint selection is a separate engineering task in itself; a standard paint system wears out quickly in this environment.
The risk of a rarely-used crane
Cranes installed for reactor and equipment maintenance are used only a few times a year. Long periods of inactivity cause brakes to stick, grease to harden and contactors to oxidise.
For these cranes, maintenance is tied to the calendar rather than operating hours, with periodic no-load runs performed regularly.
Typical solutions
| Condition | Solution |
|---|---|
| Explosive atmosphere zone | Ex-proof design, certified components |
| Corrosive vapour | Material selection and heavy-duty paint system |
| Cleaning requirement | Cleanable surface, water-shedding detail design |
| Reactor maintenance | High lifting height, precise positioning |
| Low usage | Calendar-based maintenance, periodic no-load runs |
| Critical downtime | Spare parts stock and fast service |
Frequently asked questions
One part of my facility is Ex-rated, the other isn't. What now?
All the zones the crane will work in are assessed. If the crane enters the Ex zone, it's designed for those requirements; solutions involving zone-restriction systems may also be possible.
Do I need a stainless crane?
Not always. What matters is the substances present in the environment and the cleaning regime; in most applications a suitable paint system and an elevated protection rating are enough.