Breather Vents


Assentech have extensive experience in the supply, installation and servicing of tank top equipment, as well as a full understanding of the theory, standards and legislation that applies.

As well as sizing, supplying and installing tank top equipment, we also service in-situ and refurbish, test and re-certify at our purpose built valve center – one of only 2 Groth Approved Repair Dealer workshops in Europe.



Groth Approved Repair Dealership


How Can Assentech Help?

Customers involve us in their tank venting requirements for a number of reasons including;

  • New requirements
  • Problem venting applications
  • Equipment Upgrades
  • Leakage testing of installed base – you should get an air rush when you lift a gauge hatch else your vents may be leaking
  • Refurbishment
  • Familiarisarion with API2000 6th edition
  • Checking vent sizes following pump upgrades
  • Installation of emergency relief vents
  • Checking old vent sizing to assess whether equipment is deemed fit for purpose under current standards
  • Fitting flame arresters to existing vents
  • VRU Optimisation
  • Reducing nitrogen bills
  • Servicing current equipment
  • Training site staff on tank venting and API2000
  • Calculating how much vapour losses are costing
  • Calculating the breathing requirements of a tank


New Product Selection

Our specialist software allows us to estimate your losses, calculate the flow rates your tanks require and size new vents accordingly – all of which is offered as part of the service.

We understand tank venting and the important links between vents, VRU’s, flame arresters and blanketing systems and are happy to talk through your P&IDs with you.

Replacements & Upgrades

If you are concerned about the size or performance of your tank vents we would love to talk to you.

Legislation has changed regarding vent sizing and events that were installed 5 years ago may no longer be deemed suitable. We carry out free of charge site audits which help you know where you stand with respect to current legislation.

If your system is not performing how you would expect then there is likely a problem – we will gladly carry out an inspection of your equipment and advise of what steps need to be taken to get better performance.

Inspection & Testing

As a Groth approved repair dealer we carry out inspections of storage tank equipment and both on-site and off-site leakage testing. We provide this service for all makes of equipment.


We install tank vents, emergency vents, blanketing valves and relief valves. Our engineers are fully insured to work on COMAH sites and provide Risk Assessments and Method Statements in advance as standard.


We specialise in the refurbishment, testing and re-certification of breather vents, P/Vs and ERVs at our purpose built valve center in the South West – one of only 2 Groth Approved Repair Dealer workshops in Europe.

We carry our all sorts of refurbishment to valves of all material, including exotics and fibre reinforced plastics. We provide this service for all makes of equipment.

In-Service Support

We can tailor reactive and planned maintenance services to suit your needs as a customer and the specification of your equipment. Typically with tank venting equipment, we would recommend periodic visual inspections and in-situ pressure tests. Any vents which require further work can be fully refurbished, tested and re-certified at our premesis.

We have a purpose built mobile test rig which allows us to pressure test vents on site and at the tank top as required. We use this to test the integrity of the seal since this can only be achieved through pressure testing.

We do not weight lead since this is money for old rope. Weighing the lead tells you the weight of your lead – not whether the vent is performing. If you are paying to have your pallets weighed your supplier is providing an unnecessary service.

We provide this service for all makes of equipment.

Technical Seminars

If you or your team want to know more about tank venting or get up to speed with the latest changes to API2000 we will be happy to run a technical seminar or lunch and learn session for you. We make no charge for the sessions for end users or groups of 5 or more people.