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Pressure Relief Valve deflagration- and endurance burning-proof

  • requires only 40% overpressure to reach full lift
  • due to 40% technology, higher set pressures can be used, resulting in reduced product loss, as compared to conventional 100% technology (compare API 2000)
  • extreme tightness, resulting in lowest possible product losses and reduced environmental pollution
  • valve pallet is guided inside the housing to protect against harsh weather conditions
  • can be used as a protective system in areas with potentially explosive atmospheres in accordance with ATEX
  • high flow capacity due to large FLAMEFILTER® cross section
  • PROTEGO® flame arrester unit provides protection against atmospheric deflagrations and endurance burning
  • integrated PROTEGO® flame arrester unit saves space and weight and reduces costs
  • PROTEGO® flame arrester unit is protected from clogging and sticky substances caused by product vapors
  • minimum pressure loss of the PROTEGO® flame arrester unit
  • flameproof condensate drain
  • maintenance-friendly design

Function and Description

The deflagration-proof and endurance burning-proof BE/HR-D type PROTEGO® valve is a highly developed pressure relief valve with an integrated flame arrester unit. It is primarily used as a device for flame transmission proof outbreathing on tanks, containers and process engineering apparatus. The valve offers reliable protection against excess pressure and prevents product losses almost up to the set pressure; it also protects against atmospheric deflagration as well as endurance burning if stabilized burning occurs. The PROTEGO® flame arrester unit is designed to achieve minimum pressure drop with maximum safety. The BE/HR-D valve is available for substances of explosion group IIA (NEC group D MESG > 0.9 mm).

When the set pressure is reached, the valve starts to open and reaches full lift within 40% overpressure. The tank pressure is maintained up to the set pressure with a tightness that is far superior to the conventional standard due to our state of the art manufacturing technology. This feature is ensured by the valve seats made of high quality stainless steel and with individually lapped valve pallets (1) or with an air cushion seal (2) in conjunction with high quality FEP diaphragm. After the excess pressure is discharged, the valve reseats and provides a tight seal. If the set pressure is exceeded, explosive gas/product-vapour air mixtures are released to the atmosphere. If this mixture ignites, the integrated PROTEGO® flame arrester unit (3) prevents flame transmission into the tank. If additional mixture continues to flow and stabilized burning occurs, the integrated flame arrester unit prevents flashback as a result from endurance burning. The valve is protected and also fulfils its function under this severe service conditions. The spring loaded weather hood opens as soon as the fusible element (4) melts.

The valve can be used up to an operating temperature of +60°C / 140°F and meets the requirements of European tank design standard EN 14015 – Appendix L and ISO 28300 (API 2000).

Type-approved in accordance with the current ATEX Directive and EN ISO 16852 as well as other international standards.


To select the nominal size (DN), please use the flow capacity chart on the following page

DN150 / 6" 200 / 8"
NG400 / 16"400 / 16"
a600 / 23.62600 / 23.62
b545 / 21.46545 / 21.46
c485 / 19.09485 / 19.09NG = Nominal size
Dimensions in mm / inches

Material selection for housing

HousingSteelStainless Steel
Valve seatStainless SteelStainless Steel
Weather HoodSteelStainless Steel
Flame arrester unitAB
Special materials upon request

Material combinations of flame arrester unit

Design  AB
FLAMEFILTER® cageSteelStainless Steel
FLAMEFILTER®Stainless SteelStainless Steel
Special materials upon request

Material selection for valve pallet

Design ABC
Pressure range [mbar]
[inch W.C.]
+2.0 up to +3.5
+0.8 up to +1.4
>+3.5 up to +14
>+1.4 up to +5.6
>+14 up to +35
>+5.6 up to +14
Valve palletAluminiumStainless SteelStainless Steel
SealingFEPFEPMetal to Metal
Special materials and higher pressure settings upon request

Selection of explosion group

MESGExpl. Gr. (IEC / CEN)Gas Group (NEC)
> 0,90 mmIIAD
Special approvals upon request

Flange connection type

EN 1092-1; Form B1
ASME B16.5 CL 150 R.F.
other types upon request

Design Types and Specifications

The valve disc is weight-loaded.

Pressure relief valve, basic design


Additional special devices available upon request


Pressure: +2.0 mbar +35 mbar
+0.8 inch W.C. +14 inch W.C.
Higher pressure settings upon request.

Flow Capacity Chart

The flow capacity charts have been determined with a calibrated and TÜV certified flow capacity test rig. Volume flow V in (m³/h) and CFH refer to the standard reference conditions of air ISO 6358 (20°C, 1bar). For conversion to other densities and temperatures refer to Sec. 1: “Technical Fundamentals”.