Emergency Relief Vents

Emergency Relief Manways

CNC 121 Series of Emergency Relief Manways

Emergency Relief Manway

IPTech Tank Protections CNC 121 Series are supplied to exacting quality standards and backed by over 40 years experience. They are available with a variety of options which include

  • Sizes range from 10″ (250mm) to 36″ (900mm).
  • Made from Carbon Steel and Stainless Steel, Aluminium covers also available
  • Manufactured to clients flange requirements
  • Non flanged option available
  • All manways are set and tested to the clients requirement up to 90Mbarg
  • Various designs available to suit your requirements
MTP 121 Series non-sparking emergency relief manhole covers permit access to low pressure storage tanks and provide emergency venting capacity in the event of fire. They are used extensively on bulk storage tanks, including floating roof tanks.

Table 1. Emergency Relief Vent Options


Materials / Options

Size Range

10", 12", 18", 20", 24", 26", 28", 30", 32", 34", 36"

Process Connections

API 650 (20" and 24"), ANSI 150#, Special at no extra cost


Aluminium, Cast Iron, Carbon Steel, Stainless Steel, Special

Diaphragm & Insert



Lead Plate (standard), Stainless Plate (special)

CNC121/CNC122 Emergency Relief Valve

Emergency Relief Vents

Pressure and Vacuum Emergency Manway

Emergency Relief Manway with vacuum, Fitted with spring loaded vacuum relief

Access Manway

Lockable Manway / CNC 171 / Access Hatch