Petroleum Bottom Loading Arm

WSI’s range of bottom loading arms for petroleum products are specifically designed for refined products such as gasoline, diesel, kerosene, ethanol, and lube oils etc. Whether for bottom loading multi compartment fuel trailers or a single compartment rail car there is a WSI bottom loading arm to suit the particular application. All bottom loading arms are of modular design with TTMA flanged connections of all the major components, thus allowing simpler arm configurations and superior maintenance capabilities. Inlet flange connection is ANSI #150
Petroleum Bottom Loading Arm


  • Designed in accordance with API RP 1004:2003
  • Standard size is 4” however all models are available in 2”, 3” x 2”, 3” and 6” for vapor recovery, fleet fueling, rail car and river barge application
  • Base Joints are all carbon steel with Split Flange swivel joints, either WL2 Dual Race or WSS Single Race
  • Typical swivel joint elastomers are Viton GF™ with a choice of Nitrile, PTFE, EPDM or Kalrez™ if required
  • Arms are balanced by HD compression spring
  • Alternative balance mechanisms; gas strut, counterweight, pneumatic and hydraulic
  • Primary pipe in aluminum, TTMA flanged. Carbon or stainless steel available
  • Apex and Outboard swivel joints in aluminum, TTMA flanged. Carbon and stainless steel available
  • API coupler, dry break style coupler or refueling nozzle interface
  • SS Braided hoses where applicable

Bottom loading arms are offered in standard length/height configurations or custom sized to suit the exact application.

For “up and over” petroleum hose loaders WSI can provide up to a 7 arm crossover to operate within the API envelope with our W601-H +AS model, or up to 5 arm crossover with all other “up and over” models.

See the Petroleum Bottom Loading Arm Options tab for optional equipment such as parking adapters, proximity switches, grounding and rack monitors, grounding straps etc.

All WSI bottom loading arms are designed and manufactured within our certified ISO quality management systems and in line with ASME B31.3 Process Piping code. All Bottom loading arms and swivel joint assemblies are100% hydro tested. Dye penetrant testing and Radiography carried out to required specifications. Full manufacturing documentation and MTR’s can provided with each loading arm. Standard paint finish for carbon steel is shot blasting to SA 2 ½ and Poly Urethane RAL 7035 paint finish. Specific painting specifications also provided. If required, TPI will be provided