All of the conditions on which to decide the requirement for a shelter over pumps are closely related.
1). Geographic Location of the Plant - Is the plant located in the Arctic North or in the open Saharan Desert?
2). Weather Conditions -Is it very cold, very hot, very wet?
3). Type of Pumps -During maintenance will the pump internals and parts be subjected to even more damage because they are exposed to the elements.
4). Frequency of Maintenance -If maintenance is infrequent then a portable shelter might be considered. However if the pumps and the related facilities are subject to constant attention and one or all of the items above are present then a permanent shelter should be considered.
5). Employee Turnover -If all of the previous conditions exist and you do not spring for a permanent shelter then you may have trouble keeping trained and experienced employees on the payroll.