Vapor Emission Control System



  • Minimizing the emissions of VOCS (Volatile Organic Compounds) from oil tankers during the fluctuating ambient conditions experienced during sea voyages is important from both environmental and commercial points of view.
  • The controlled release is often undertaken when the gas pressure approaches a pre-set point. However, it is not always clear at what pressure a manually controlled release should be stopped. Without this information, excess vapours can be released, causing air pollution and a loss of cargo.
  • To meet this challenge, a VECS and Reporting System can be used to control the vapour pressure in oil cargo tanks to minimise and fully control VOC emissions. Designed to comply with the latest international rules and regulations it is equipped with an advanced reporting system.
  • The VECS is installed on the mast riser’s bypass line, and controls the vapor pressure in all the cargo tanks during voyage for direct emission control, in order to reduce VOC loss from the tanks during voyage
  • By controlling the pressure in the venting system, it is possible to fully control the VOC emissions.
  • The VECS can be programmed to enable adjustment of the opening setting on the valve, according to what is optimal for the specific cargo.

Rules & regulations

  • SOLAS 74 Chapter II-2 Reg. 59. : Venting, purging, gas-freeing and ventilation.
  • IMO MSC/Circ. 731. : Revised factors to be taken into consideration when designing cargo tank venting and gas-freeing arrangements.
  • IMO MSC/Circ. 680. : Systems and Operations/VOC Management plans
  • USCG CFR 46 Part 39. : Vapor control system. – ISO 15364:2007 : Ships and marine technology
  • pressure/vacuum valves for cargo tanks.


  • Remotely controlled opening/closing from C.C.R
    (Cargo Control Room)
  • Setting value
    – Opening pressure & Closing pressure :
    1,700mmW.G ~ 1,500mmW.G (adjustable)
    – Opening vacuum & Closing vacuum :
    -200mmW.G ~ -100mmW.G (adjustable)
  • Adjustable of open/close pressure from C.C.R
    – Opening setting and closing pressure are programmable
  • Manual venting function
  • Full open/close remotely by manual operation
  • Operable from C.C.R (Cargo Control Room)
  • The emission of V.O.C can be automatically controlled during the voyage.
  • Emitted V.O.C flow rate can be recorded and printed.
  • Explosion proof approved electric actuator (EX d IIB T4)
  • Electric power source : AC 220V, 1Ph, 60Hz
  • PLC unit for set adjustable and opening / closing pressure
  • Signal : 4~20mA DC input.
  • Hydraulic or electric actuator on request
  • Local Hydraulic Power Unit (LPU)