46 CFR §154.315

1. (a)Cargo pump rooms and cargo compressor rooms must be above the weather deck and must be within the cargo area.
2. (b)Where pumps and compressors are driven by a prime mover in an adjacent gas safe space:
   1. (1)The bulkhead or deck must be gastight; and
   2. (2)The shafting passing through the bulkhead or deck must be sealed by a fixed oil reservoir gland seal, a pressure grease seal, or another type of positive pressure seal specially approved by the Commandant (CG-ENG).