CHOOSING the RIGHT breather valve (pressure vacuum relief valve) – Our Quality is Your Peace of Mind

 Quality - peace of mind-reduce Vapour loss from volatile liquids stored in fixed roofs tanks

Vapour loss from storage tanks has long been a subject of concern to storage tank owners and operators. Reducing and controlling the evaporation from storage tanks plays a key role in maintaining product quality, protecting the environment and promoting safety.

Storage tank breather valves perform an important role in :

When CHOOSING the RIGHT breather valves, It is of vital importance that companies make informed choices and not to base their buying decisions around the price alone when the actual cost difference between quality (peace of mind) and potentially unregulated products is negligible in the long-term scheme of things.

Breather valves ( Pressure Vacuum Relief Valves) are important devices which are used to reduce Vapour loss from volatile liquids stored in fixed roofs tanks

Here are the top 7 questions Assentech has come up with to help buyers make the right (and safe) choices:

  • Ensure the vents are supplied with leakage and calibration certificates. Leakage testing is now part of ISO 28300 or API 2000. Most manufacturers supply only calibration certificates (not including the leakage tests) which are now technically in contravention of API 2000. Testing each vent takes a minimum of 1 hour at the factory and is not something most manufacturers include with every vent. It is usually a cost adder option but we include it in our basic price.
  • Air cushioned pallets? (This will increase the valves sealing ability = better safety/air quality)
  • Ensure your breather vent has a current pressure and vacuum leakage test certificate which is stipulated by industry Standard, ie, for vents up to 6″ this is 0.5 SCFH at 75% of set point.
  • What do the weights look like and what are they made of? Sounds strange but if they are just lumps of lead they will not have the weight distributed evenly = leakage risk. We regularly come across food industry applications with lead weights fitted to vents.
  • Preferably FEP Teflon diaphragms to ensure maximum performance.
  • Ensure Manufacturers perform leakage test on the vacuum port in addition to the pressure port.
  • Are the seats and pallets of a robust enough material (e.g. SS316) to cope with any environmental impacts and wear? (for example an Aluminium valve with an aluminium seat and pallet will wear out much quicker than an aluminium valve with SS316 seat and pallet at a marginal difference in cost)
  • For applications within the pharmaceutical, food and drink industries Valves must be supplied with stainless steel weights. This is more expensive to supply than lead but lead is obviously a big problem for applications within the pharmaceutical, food and drink industries. Do we really want a risk of ingestion?
  • Ensure the cover bolts are on the outside of the seal. This is a leakage path and the reason why few other manufacturers certify leakage rates.
  • Ensure pipe-away vents include drains behind the outlet flange. We have experienced many cases where the outlet pipes trail upwards and do not self-drain. This creates the risk that the pressure pallet can freeze onto its seat as it is constantly immersed in condensate.
  • Many vents on the market are fabricated, not cast. This can create corrosion issues.
  • Does your supplier really understand your application and is not just interested in getting the sale quickly? Can they offer you sound advice, reliable performance data and detailed product specification sheets? If the supplier shows no interest in the application and says ‘a vent’s a vent’ – walk away! Your staff and your facility are too precious to place into the hands of suppliers that just want your PO number. It takes extra effort, but talk to a few suppliers and compare the advice you get. You’ll know when you are dealing with someone who knows what they are talking about.
  • Have you had enough advice to ensure that each valve is adequately sized and delivers the right flow for the conditions it is installed in? (We’ve all heard of sucked in tanks! £££s)
  • If it’s a Flame Arrestor, is it specified to the correct Gas Group for your process? (These have changed in the past few years and products such as ethanol now come under the more rigorous Gas Group IIB1)
Our service company, Assentech Rapid Response & Service Ltd, is servicing and testing tank breather vents for an ever-increasing number of customers on all brands of breather valves. They have found the most common cause of excessive leakage on carbon steel emergency vents is rust scale build up behind the pallet diaphragm. This prevents the pallet from sealing on the seat ring. A recent service of Groth vents provides the ideal opportunity to share the design integrity of this product:
The vent photographed is a carbon steel 2000A model, approximately six years old. Even though these vents are carbon steel, Groth still makes the lid and seat ring out of stainless steel to ensure the functioning interfaces keep their integrity for the whole life of the valve. This valve will continue to function as new for many years to come. With increased focus on emissions to the environment, features like this will become increasingly important as operators come under tighter pollution controls with an ageing plant.
Emergency Pressure Relief Valve
Emergency Pressure Relief Valve
Emergency Pressure Relief Valve
Emergency Pressure Relief Valve

 Assentech supply, install and service full range of storage tank and fluid transfer equipment in the UK and Europe.

At Assentech, we supply a broad range of services to the fluid process, transfer and storage industries.

We provide technical assistance, installation and maintenance for all of the products we offer, as well as for similar equipment from 3rd party manufacturers.

 

Some of our customers testimonials


Emergency-Relief-Valve-Pilot-Operated-2500a  Assentech- pilot operated pressure relief valves service and calibration

After conducting a Third Party Witness Inspection, I was most impressed with Ewart and his team, their professionalism, and product knowledge I found to be excellent.

Ian Johnston

Director, RAK Inspection


Emergency-Relief-Valve-Pilot-Operated-2500a  Assentech- Geodesic Dome Installation

Assentech were subcontracted to assemble and install a 25m geodesic dome for Shaft G on the Lee Tunnel project. My experience with Assentech from pre-contract through to assembly has been very positive. Unlike other subcontractors I have experienced on this project, Assentech had a very positive attitude to producing the level of documentation required for a project of this scale. Leading to a high quality pre construction packaged approved in a timely manner. The communication regarding the manufacturing process was first class allowing us to easily plan our works and prepare the site. Dome assembly was carried out very efficiently and completed to programme. The task was correctly resourced and well supervised. The work force had a positive attitude and carried out the task safely. In summary from my perspective it has been a very easy subcontract to manage with a high quality finished product.

Robert Colthorpe

Site Agent – Lee Tunnel Project, Morgan Sindall


Emergency-Relief-Valve-Pilot-Operated-2500a  Assentech wins supplier excellence award from Eastman Chemicals

We were extremely pleased with the level of service and professionalism demonstrated by Assentech, right from our initial enquiry, through delivery and post installation. As a recipient of only two of these awards made by Eastman Chemical Company in the UK, based on performance in 2014, Assentech are rightly proud of their achievements.

Robert Dodgson

TH3 Project Procurement Lead, Eastman Chemical Company


Emergency-Relief-Valve-Pilot-Operated-2500a  Assentecha-IFR Installations at Vopak, Teesside

As you said “you delivered what it said on the tin”. On time and on budget.  Your up front engineering to determine the suitability of your product for our application was second to none, i have not seen anyone else in the industry pay as much attention to detail before you get the purchase order number as Assentech.

Garry Lee

Project Manager, Vopak Limited


Emergency-Relief-Valve-Pilot-Operated-2500a  AssentechIFR Installations at Navigator Terminals

Assentech have supported our Navigator Terminal (formerly known as Vopak Teesside) on two important ~
projects by providing technical assistance and supplying and fitting a total of 11 Internal floating roofs. Both projects have been completed on schedule and on budget. Assentech have provided an excellent level of experience and front end engineering support with high quality drawings and documentation. Their specialist on site labour have worked collaboratively with us and Assentech have proven to be open, honest and flexible partners.
We have experience of both their Heavy Duty Pontoon type and Full Contact IFR’s and we continually monitor operation and performance of all lFR units Installed on site and consider the Assentech supplied Matrix brandto be the best in the market with exceptional build quality and rigidity. Our clients have inspected the installations and have always remarked upon the build quality and have been impressed with their strength in fully supporting up to four people without noticeable deformation. The design and construction of their stainless steel shoe seals continue to prove to operate excellently with no noticeable reduction in performance or flotation ability over the time since Installation.
Assentsch have proven to be extremely competitive on price and their installation and inspection activities have always been thorough. Navigator therefore have no hesitation in recommending Assentech to other companies considering their services.

Brian Beddow

Project Manager, Navigator Terminals Seal Sands