“With over 40 years experience in the Low Pressure tank market, we are perfectly placed to offer products designed and engineered to last.”

  • Quality Assurance to ISO9001:2008
  • PED 97/23/EC
  • ATEX Directive 94/9/EC


B400 Series Emergency Relief Manway Specification


The B400 Series ensures that tanks and vessels are kept safe during periods of excessive pressure due to external fire sources and also allows access to the tank for inspection / cleaning purposes.

  • Standard Pressure settings + 4 mbarg to 140 mbarg
  • Size range 6" ( 150 mm ) – 36" ( 900 mm )
  • Standard body materials – Aluminium, Carbon steel, Stainless steel
  • Diaphragm material - PTFE
  • Machineable seats
  • Standard drilled flanges – ANSI / DIN / API
  • Automatic re seat
  • Non standard applications – Consult factory



Non Standard Applications - There are numerous options available for special applications. Exotic materials such as Hastelloy, Monel and various plastics can be offered to suit the most hazardous of environments. Special coatings can also be applied for extreme service. For low temperature duties, internal parts can be PTFE coated to prevent seizure.

  • 3B Controls Ltd manufacture a comprehensive range of safety relief valves.
  • Our goal is to meet your requirements !
  • We aim to produce low pressure safety relief valves that exceed the industry standard and to deliver them in less than four weeks.


3B Controls Ltd has achieved accreditation to the following: Quality Assurance to ISO 9001:2000 • PED 97\23\EC • ATEX Directive 94\9\EC

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We have finalised our Corporate Presentaion and compiled it with a PDF catologue. Please email us to request the CD to be posted to you.