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Frequently Asked Questions

FAQ

Please see our frequently asked questions and answers below or call our experts direct on +44 (0) 1384 881 188 to ask a question directly.

FlexEJ About Us People

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On all stock items ordered.
Mon-Thur by 2pm, 10am Fridays

Design & Manufacturing
Full in-house design & manufacture to EN / ASME / PED.

ISO14001 Accreditation
FlexEJ has an accredited Environmental Management System.

Frequently Asked Questions​

If you have any questions you would like to ask us directly please use the Contact Us form below or call us on +44 (0) 1384 881 188 or use the Live Chat facility for an immediate response to anything you require. Please see our frequently asked questions and answers below. Use may also use the form to ask a new question about FlexEJ’s products and services.

About FlexEJ​

A. Yes, please call us with your details. For sales assistance please contact us or use our Live Chat facility. See also our web shop – secure purchasing with 24hr delivery.

A. Yes, take a look at gallery page to see examples of what we offer and/or have designed and built for previous customers. For sales assistance please contact us or use our Live Chat facility.

A. For in-stock items, standard items ordered via our web shop we offer 24hr delivery (if order placed by 13.00hrs). Please see our web shop for more details. Other items : typically 7-14 working days. Engineered or special items will be individually quoted. For sales assistance contact us or use our Live Chat facility.

A. Bank details for payments in GBP, Euro and USD can be found via pdf file on our support page. For sales assistance please contact us or use the Live Chat link on this page.

A. Yes, subject to the normal checks, please download our application form. For sales assistance please contact us or use the Live Chat link on this page.

A. Yes, FlexEJ is accredited to ISO9001:2015 and ISO14001:2015. For sales assistance please contact us or use the Live Chat link on this page.

A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.

A. The range of suitable applications and corresponding PE(S)R assessment is stated for this product in the product’s Technical Information tab. If you have any doubt or question that your intended application falls outside the SEP application range please contact us and we will be pleased to advise. For a full explanation of PE(S)R see here

Air & Dirt Separators

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

A. Yes, the majority of FlexEJ’s current range of Air and Dirt Separators are available from the FlexEJ shop on a same-day despatch basis although our largest Air and Dirt Separators (DN100 to DN150) need to be pallet-delivered and require an extra 2-3 days for delivery. We can also supply Air and Dirt Separators on an ongoing OEM basis and can cater for custom requirements. Please ask for details.

A. Most of our air & dirt separators are available from stock on a 24hr delivery basis. Non-stock separators or custom-manufactured items typically take 7-14 working days, depending on options and quantities required.

Applications

A. There are three broad applications which may exist in any combination: > to reduce vibration or noise being transmitted through the piping > to allow for installation misalignment in the piping > to allow piping to move in operation, normally due to thermal growth, so to avoid high pipe stress and loads on equipment. If significant thermal movement is expected, a pipe stress analysis should be carried out for the system and that analysis will identify the ideal location for any expansion joints required to achieve acceptable pipe stress and loads. For technical assistance contact us or use our Live Chat facility.
A. To design or select a rubber bellows or metal expansion joint we need to know: nominal bore, end type, service, temperature, pressure and required movements. You may also specify in addition your requirements for external hardware – tie rods, hinges, gimbals – internal liner, external cover and instrumentation. Material selections should also be specified to suit the service and associated system piping. For technical assistance please contact us or use our Live Chat facility.

A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.

A. Do use FlexEJ’s new Bellows Finder available on our Expansion Joints page to find recommended expansion joints by media (application) such as waters, oils, acids, etc, as well as by bore size, length, end type and more. Generally speaking, any of our HVAC bellows (rubber or metal) might be suitable for general purposes whereas our high-quality Elaflex ranges are recommended for more specific requirements you may have. And metal expansion joints can generally be designed and built to accommodate any media and temperature range, environment and pressure ranges you are likely to encounter. Do call us or use LIVE CHAT for more direct advice.

Commercial Buffer Vessels

A. A buffer vessel is a storage tank – in the case of a DHW system it stores hot water. This water is immediately available to the DHW consumers and eliminates any delay in the heat source coming on line or up to temperature.
A. That depends on the heat source you have and the demand on the DHW draw off. If the heat source is constantly available, always at the correct temperature and capable of supplying the peak demand of DHW then no, you don’t need a buffer vessel. In a practical system it would be expensive and inefficient to meet those criteria so a buffer vessel is normally included.
A. This depends on the capability and availability of the heat source and the peak demand of the DHW system. The correct buffer vessel volume allows an economic and energy efficient design to be achieved.

A. We would recommend using the FlexEJ PhexPak as it provides isolation and control in one convenient package.

A. The buffer vessels do not have specific approval number but are suitable for potable water and meets the needs of a Water Regulation 4 material approval due to being 100% 316 stainless steel.
A. Yes, all of our standard buffer vessels are supplied with an industry standard 2¼” boss to fit an immersion heater.

A. Yes, there is a 2½” connection on top to accommodate up to the largest size commercial TPRVs.

Dosing Pots

A. All our stock chemical dosing pots come preconfigured using DN25 PN40 female-threaded ball valves. We can manufacture to other specifications but not from stock.

Elaflex Rubber Bellows

A. Yes. FlexEJ holds a large stock of the most popular sizes and types of Elaflex rubber bellows as well as our HVAC value bellows range. We also hold stock of the most popular metal bellows for HVAC. Many of these items are available on 24hr delivery from our online web shop. We can also manufacture to order. For sales assistance please contact us or use our Live Chat facility.

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

A. Please refer to our guidelines for installation, anchoring & guides. They are available in the Downloads section of this website: Elaflex Rubber Bellows Installation Instructions and FlexEJ Metal Bellows Installation Instructions. For technical assistance please contact us or use our Live Chat facility.

A. Yes, our Elaflex ERV-R and ERP rubber bellows have WRAS, DVGW and ACS approval for drinking water. The Safetech manufactured to order rubber bellows can be supplied with WRAS approved EPDM linings. Our MRCA copper ended metal expansion joints also have WRAS approval. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. The ERP Redspot, ERV-R Redband and Rotex DoubleRed bellows are now available from FLEXEJDIRECT from stock for the most common sizes and configuration of these popular high-quality bellows. The shop items and can be despatched same day (Monday to Thursday) on a 24hr service if in stock. More advanced configurations and the other nine Elaflex bellows ranges are available to assemble to exact specifications and typically take 7-10 days (depending on size, quantities and configurations required).

Expansion Joints

A. Spring rate is the reaction force of the bellows when it is moved. It is a different force to pressure thrust – both forces act together on the piping. For technical assistance contact us or use our Live Chat facility.
A. This is a metal bellows term : ply refers to the number of sheets of metal used in the forming of the bellows, so a 2 ply bellows is made from two sheets of material. A multi ply bellows is generally more flexible that an equivalent single ply bellows. For technical assistance please contact us
A. In this field, the terminology can be confusing, often with no universally accepted meaning. We tend to use the following definitions but the terms “bellows” and “expansion joint” are typically considered as interchangeable: > Expansion Joint – an expansion joint is a complete unit with metal bellows or rubber bellows and end fittings, plus, optionally, liner, cover and external hardware. Other terms used : compensator, flexible connector. > Rubber Bellows – the flexible element within a rubber expansion joint > Metal Bellows – the flexible element within a metal expansion joint > Liner – The liner fits within the expansion joint under the metal bellows or rubber bellows to prevent the flowing media directly impinging on the bellows. This this reduces flow disturbance and allows the temperature of the bellows to be controlled in the design. For technical assistance please contact us or use our Live Chat facility.

A. A tie rod is a simple pressure thrust restraint. It will allow reasonable lateral movement but not axial extension; it can allow axial compression if the pressure thrust is overcome by the piping movement. See the movements and pressure thrust FAQs for definitions. For technical assistance please contact us or use our Live Chat facility.

A. All expansion joints exert a force, pushing the pipe ends apart – pressure thrust – which is proportional to the operating pressure and diameter of the bellows. If the expansion joint is unrestrained the piping system must withstand the force, or, alternatively, the expansion joint may have restraints built in to constrain the pressure thrust force. For instance types, tie rod, hinge or gimbal. For technical assistance please contact us or use our Live Chat facility.

A. To design or select a rubber bellows or metal expansion joint we need to know: nominal bore, end type, service, temperature, pressure and required movements. You may also specify in addition your requirements for external hardware – tie rods, hinges, gimbals – internal liner, external cover and instrumentation. Material selections should also be specified to suit the service and associated system piping. For technical assistance please contact us or use our Live Chat facility.

A. The EJMA is the Expansion Joints Manufacturers Association. Their bellows calculation method is most frequently used for metal bellows expansion joint design. EJMA does not cover rubber bellows or metal hose design. For technical assistance please contact us or use the LIVE CHAT link on this page.

Low Loss Headers

A. Yes, to some extent, as the flow velocity in the body is low. We provide a Flamco AAV and DN25 drain valve on all FlexEJ low loss headers. However, separation is not as efficient as using a dedicated air/dirt separator as the main low velocity section in the LLH is bounded by turbulent cross flows.

A. Opinions vary but ideally all the primary circuit and secondary circuit flow and returns should be brought together in horizontal manifolds before connection to the low loss header.

A. On a vertical low loss header the returns connect at the bottom and the flows at the top. If the connections are staggered side to side then the lower pair are normally the primary side.

A. Sizing can be expressed in terms of flow rate or power. In heating systems, the total boiler power in the primary circuit is often taken as the sizing criteria. The power rating is directly proportional to the flow rate and temperature difference as given by m.Cp.Δt – Power (kW) = Mass flow rate (kg/s) * Specific Heat of Water (kJ/kg°K) * Temperature difference (°K). Our product table above shows both nominal flow rate and power ratings.

A. We have an online low loss header calculator we’ve built to help you – or do  please get in touch with the details of your system and we will be pleased to help.

A. Based on the flow rate through the low loss header the body is sized to achieve a very low flow velocity – typically less than 0.3m/s. This low velocity ensures a low pressure drop between flow and return.

A. Yes – strictly speaking hydraulic separation between circuits is achieved using a low loss header.

A. A low loss header (LLH) provides hydraulic separation between multiple pumped circuits. This allows each circuit to operate independently and to be controlled for optimum efficiency. The header presents very low pressure drop bypass between the flow and return. FlexEJ low loss headers are provided with sensor ports on all four branches so whatever control system is being implemented you will have the port you need.

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

Manufacturing

A. Yes, we can package the vessel with associated piping, valves, instrumentation and equipment, skid mounted or free standing. To view some examples of our past projects, go to the pressure vessels page and scroll down to the gallery. For technical assistance please contact us or use our Live Chat facility.

A. Yes, FlexEJ designs and manufactures engineered pressure vessels to PED, ASME 8, EN13445 and PD5500 as required – plus customer specifications. We can also manufacture to your design and drawing. For technical assistance contact us or use our Live Chat facility.

A. Yes, FlexEJ is accredited to ISO9001:2015 and ISO14001:2015. For sales assistance please contact us or use the Live Chat link on this page.

A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.

A. If you have any questions you would like to ask us directly please use LIVE CHAT or call us directly on 01384 881188 or use the CONTACT US form and we’ll get back you asap, usually within 24hrs, sooner if more urgent.

Metal Bellows

A. Yes. We hold stock of the most popular metal bellows for HVAC. Many of these items are available on 24hr delivery from our online web shop. We can also manufacture to order. For sales assistance please contact us or use our Live Chat facility. In addition, FlexEJ holds a large stock of the most popular sizes and types of Elaflex rubber bellows as well as our HVAC value bellows range.

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.

A. Yes, if you have the details we can normally offer an equivalent, our FAQ here gives the information we will need for a full selection. For technical assistance please contact us or use the Live Chat link on this page.

A. To identify an existing expansion joint we need to know: nominal bore, overall length and flange type plus service, temperature, pressure and required movement if known. Try our Flange Finder to help identify the flange and you can send us a picture of the existing part using the Contact us form. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Yes, our MRCA copper ended metal expansion joints also have WRAS approval. We laso have DWI approval for stainless steel expansion joints. For technical assistance please contact us or use the Live Chat link on this page.

Metal Hose Assemblies

A. Yes, a strip wound hose can be used as a liner within a convoluted metal hose assembly. Flexibility is reduced to some extent. For technical assistance contact us or use our Live Chat facility.

A. A jacketed hose has a second outer hose over the inner which allows (typically) a cooling or heating medium to be introduced. An example is shown in the gallery : scroll to the bottom on the metal hose page. For technical assistance contact us or use our Live Chat facility.

A. The bend radius depends on the hose diameter and the type of motion. The static bend radius is the minimum radius the hose can bend to for a few movement cycles without fatigue failure. The dynamic bend radius is the minimum radius the hose can bend to for many movement cycles without fatigue failure. ISO10380 defines these parameters. For technical assistance please contact us or use our Live Chat facility.

A. Metal hose is manufactured in continuous lengths from metal strip which is welded and then formed. We offer U form convoluted metal hose which is mechanically or hydraulically formed, with standard or close pitch. Typically the hose conforms to ISO ISO10380. For technical assistance please contact us or use our Live Chat facility.

A. No, we only manufacture to order but lead times can be very short. For sales assistance please contact us or use our Live Chat facility.

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

PhexPak Packaged Plate Heat Exchangers

A. A plate heat exchanger is a series of corrugated plates (usually stainless) placed in sequence to form a series of primary and secondary circuit channels that alternate throughout the plate pack.
A. Plate heat exchangers work by forcing a medium through the small channels between the plates, causing the heat to be extracted from one circuit and transferred to the other.
A. A packaged plate heat exchanger starts life as a basic plate heat exchanger, it is then combined with control components such as a primary pump, control valve, temp sensor and various other optional extras.
A. Packaged plate heat exchangers manage and optimize the transfer of flow and heat by monitoring and reacting to a temperature sensor, usually placed on the secondary flow.
A. Phexpak is a fully modular and customizable product. It can be specified and designed to meet your exact requirements.

A. Hot water requirements for commercial projects are typically calculated using CIBSE guidance to meet the required standards. We utilise BS EN806 and BS 8558 to help our customers understand their requirements and can provide suitable product options to meet those requirements.

A. In a word, yes. A packaged plate heat exchanger is a great replacement for a calorifier for the vast majority of applications.

A. Not entirely, but it will significantly reduce the risk if installed to supply DHW instantaneously due to the vastly reduced volume of water in the system when the storage element is removed.

A. In a word, yes! Like our other products, the PhexPak is available to order directly from us. Just get in touch with our sales team to start the process.

A. Plate heat exchangers are one of the most efficient ways to transfer heat in the HVAC industry, in fact they are 99% efficient with only a 1% heat loss in most scenarios. Couple this with the most efficient pumps and control components available in today’s market and you have an unbeatable solution.

A. Packaged plate heat exchangers are typically installed freestanding in a plant room, and are connected via the 4 following connection points: Primary flow, Primary return, Secondary flow, and secondary return. Power is then supplied to the control panel and the unit is ready for commissioning and setup.

A. Packaged plate heat exchangers tend to cost more than standalone plate heat exchangers, but offer a wide range of benefits that a standalone plate heat exchanger simply can’t offer. They are also supplied with all the required pumps, valves and control components fitted to ensure optimum performance of the heat exchanger.

A. A calorifier is a storage buffer vessel that holds a body of water (most commonly DHW), and has an internal coil or similar heating element which circulates a primary heating circuit, designed to indirectly heat the body of water in the vessel.

Yes, the PhexPak is a great direct alternative to the Stokvis Econoplate packaged plate heat exchanger, which is no longer available. Please get in touch for help with your requirements or to request more info on the PhexPak.
A. Yes, please contact us with your product and project requirements and we will quote the PhexPak packaged plate heat exchanger.
A. Yes, please contact us with your product and project requirements and we will quote the PhexStore. PhexStore is a direct alternative to the Econostore, which is no longer available.
A. Yes, FlexEJ can quote and supply DHW buffer vessels from our standard range up to 1000l or bespoke design and manufacture anything larger.
A. Yes, FlexEJ can offer help and support either remotely or on site if required, utilising BSEN806 and BS8558 to determine DHW requirements.
A. Yes, FlexEJ can quote and supply a huge range of heat exchangers for DHW and LTHW applications.
A. FlexEJ can quote and supply a whole host of plantroom accessories, from product specific insulation jackets to full unvented system component kits. Please get in touch with your requirements.
A. Yes, in April 2024. Please contact FlexEJ for quotes and technical assistance on packaged plate heat exchangers, buffer vessels and hybrid buffers.
Yes, in April 2024. Please contact FlexEJ for quotes and technical assistance for all your packaged plate heat exchanger, buffer vessel and hybrid buffer requirements.

Pressure Vessels

A. Yes, we can package the vessel with associated piping, valves, instrumentation and equipment, skid mounted or free standing. To view some examples of our past projects, go to the pressure vessels page or to our gallery pages. For technical assistance please contact us or use our Live Chat facility.

A. No, we only manufacture to order. For technical assistance please contact us or use our Live Chat facility.

A. Typically up to 3m diameter, 10m long, 15t weight. Please let us know your requirements and we can quickly advise if it is within our capability. There are some examples shown in our gallery – take a look by scrolling down to the bottom of the pressure vessels page. For technical assistance please contact us or use our Live Chat facility.

A. Yes, FlexEJ designs and manufactures engineered pressure vessels to PED, ASME 8, EN13445 and PD5500 as required – plus customer specifications. We can also manufacture to your design and drawing. For technical assistance contact us or use our Live Chat facility.

A. No, at present FlexEJ is not U Stamp accredited. For technical assistance please contact us or use our Live Chat facility.

A. A. PD5500 is a Specification for unfired, fusion welded pressure vessels. Formerly known as BS5500, it is a UK standard FlexEJ uses to design pressure vessels. For technical assistance contact us or use our Live Chat facility.

A. No, we only manufacture to order. For sales assistance please contact us or use our Live Chat facility.

A. To design a pressure vessel we need to know the design pressure, temperature, working fluid, volume (or length & diameter) and what material is required. The number and size of connections to the vessel has a big impact on both the design and cost so this is also useful early design information. For technical assistance please contact us or use the LIVE CHAT link on this page.

Rubber Expansion Bellows

A. Yes. FlexEJ holds a large stock of the most popular sizes and types of Elaflex rubber bellows as well as our HVAC value bellows range. We also hold stock of the most popular metal bellows for HVAC. Many of these items are available on 24hr delivery from our online web shop. We can also manufacture to order. For sales assistance please contact us or use our Live Chat facility.

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

A. Please refer to our guidelines for installation, anchoring & guides. They are available in the Downloads section of this website: Elaflex Rubber Bellows Installation Instructions and FlexEJ Metal Bellows Installation Instructions. For technical assistance please contact us or use our Live Chat facility.

A. FlexEJ Value HVAC and Elaflex rubber bellows are stocked in a number of standard lengths from 105mm to 300mm, a summary of lengths, diameters and types can be found on each product page. We also offer fully engineered rubber bellows which are available in custom lengths to suit the application. You can use our bellows finder to find the most suitable product. For technical assistance please contact us or use our Live Chat facility.

A. Yes, if you have the details we can normally offer an equivalent, our FAQ here gives the information we will need for a full selection. For technical assistance please contact us or use the Live Chat link on this page.

A. To identify an existing expansion joint we need to know: nominal bore, overall length and flange type plus service, temperature, pressure and required movement if known. Try our Flange Finder to help identify the flange and you can send us a picture of the existing part using the Contact us form. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Yes, our Elaflex ERV-R and ERP rubber bellows have WRAS, DVGW and ACS approval for drinking water, see our Elaflex pages for more information. The Safetech manufactured to order rubber bellows can be supplied with WRAS approved EPDM linings. Our MRCA copper ended metal expansion joints also have WRAS approval. For technical assistance please contact us or use the LIVE CHAT link on this page.

Safetech Large Format Rubber

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.

A. Yes, if you have the details we can normally offer an equivalent, our FAQ here gives the information we will need for a full selection. For technical assistance please contact us or use the Live Chat link on this page.

A. To identify an existing expansion joint we need to know: nominal bore, overall length and flange type plus service, temperature, pressure and required movement if known. Try our Flange Finder to help identify the flange and you can send us a picture of the existing part using the Contact us form. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Yes, our Elaflex ERV-R and ERP rubber bellows have WRAS, DVGW and ACS approval for drinking water, see our Elaflex pages for more information. The Safetech manufactured to order rubber bellows can be supplied with WRAS approved EPDM linings. Our MRCA copper ended metal expansion joints also have WRAS approval. For technical assistance please contact us or use the LIVE CHAT link on this page.

Technical - Pipe Expansion Joints

A. Yes, but all metal bellows MUST have a heavy-duty internal liner fitted. We can help you with this. Please get in touch : contact us or use our Live Chat facility.

A. The Elaflex YellowSteel ERV-GS Rubber Bellows and Elaflex YellowSteel ERV-GS HNBR Rubber Bellows are fire resistant for 30 minutes at 800 DegC. Flame protection covers are available to fit to all the Elaflex rubber bellows. For technical assistance please contact us or use our Live Chat facility.

A. Yes, typically for Elaflex rubber bellows above DN50 a vacuum support ring or spiral is required for FV, the partial vacuum performance varies by type and diameter, please refer to the product data sheets. Support rings or spirals are an option for all standard rubber bellows and may be specified for integration into all our manufactured rubber expansion joints. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Yes, some rubber materials can be used directly with abrasive material, the Elaflex YellowSteel ERV-GS HNBR Rubber Bellow and Elaflex BlueSpot ERV-BR Rubber Bellow being the most abrasion resistant. For any Elaflex rubber bellows or engineered rubber expansion joints a stainless steel internal liner can be supplied which prevents the abrasive flow from directly impacting the rubber. For technical assistance please contact us or use our Live Chat facility.

A. Yes, we can normally accommodate any combination and also different nominal bores. A selection of common flanges are shown in our Flange Finder. For technical assistance please contact us or use use our Live Chat facility.

A. Yes, you may pre-set the bellows within its existing movement capability but care must be taken to ensure the resulting movement cycle is acceptable. For technical assistance please contact us or use our Live Chat facility.

A. No, it is not recommended to join metal expansion joints together. However, we may be able to manufacture to your exact requirements so please contact us or use our Live Chat facility.

A. Yes – if correctly guided and anchored – our rubber bellows can be joined together using a mating flange to seal up on. For technical assistance please contact us or use our Live Chat facility.

A. You can use our bellows finder to find the most suitable product and our FAQs here give information. For technical assistance please contact us or use our Live Chat facility.

A. You can use our bellows finder to find the most suitable product and our FAQs here give more information. For technical assistance please contact us or use our Live Chat facility.

A. Please refer to our guidelines for metal hose installation. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. There are three types of allowable movements:

> Axial movement is the movement of the bellows or expansion joint parallel to the centre line of the expansion joint – compression and extension.

> Lateral movement is the movement of the bellows or expansion joint in a plane perpendicular to the centre line of the expansion joint

> Angular movement is the movement of the bellows or expansion joint causing the centre line of the expansion joint to follow an arc.

Rotation, end to end, is not an allowable movement and will cause the bellows or expansion joint to fail.

For technical assistance please contact us or use our Live Chat facility.

A. Very roughly, above 6 Barg / 130 DegC or above 16 Barg at any temperature a metal expansion joint will be required. For technical assistance please contact us or use our Live Chat facility.
A. There are three types of allowable movements: > Axial movement is the movement of the bellows or expansion joint parallel to the centre line of the expansion joint – compression and extension. > Lateral movement is the movement of the bellows or expansion joint in a plane perpendicular to the centre line of the expansion joint > Angular movement is the movement of the bellows or expansion joint causing the centre line of the expansion joint to follow an arc. Rotation, end to end, is not an allowable movement and will cause the bellows or expansion joint to fail. For technical assistance please contact us or use our Live Chat facility.

A. The liner deflects the flow away from the arch or convolution. This results in smoother flow, less abrasion of the bellows and can provide a reduction in bellows material temperature used in conjunction with insulation. For technical assistance please contact us or use our Live Chat facility.

A. Full material traceability / PMI, DP examination of all welds (including hose long seam), hydrotest are all typical for engineered metal hose assemblies. The certification required and applicable specifications must be agreed prior to order placement. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Standard metal expansion joints may have a pressure test certificate issued if requested with order. Engineered metal expansion joints are provided with very extensive certification depending on customer requirements, PED if applicable and industry specifications such as ANSI B31.3. The certification required and applicable specifications must be agreed prior to order placement. For technical assistance please contact us or use our Live Chat facility.

A. Our ranges have many approvals and certification. A summary for the Elaflex range of high quality rubber bellows can be found in our catalogue. The individual product data sheets for rubber bellows also show the certification and approvals. We can also provide specific material certification for all items if requested at time of PO. For technical assistance please contact us or use our Live Chat facility.

A. DN6 to DN200mm, larger possible. For technical assistance contact us or use our Live Chat facility.

A. Any standard or custom flange pattern for fixed flange or lap flange. Pipe ends and threaded ends allow virtually any end fitting to be supplied either welded or screwed. Generally it is preferred to have one end that allows rotation at installation to avoid the hose being under torsion. For technical assistance contact us or use our Live Chat facility.

A. All industry standard flanges are available or we can supply any bespoke flange design you require. Our Flange Finder contains details for many common flanges. For technical assistance contact us or use our Live Chat facility.

A. A gimbal is a pressure thrust restraint which allows angular movement in two planes and no axial movement. Gimbals are often used in pairs to create restrained expansion joints for large two plane lateral movements. See the movements and pressure thrust FAQs for definitions. For technical assistance please contact us or use our Live Chat facility.

A. A hinge is a pressure thrust restraint which allows angular movement only in one plane and no axial movement. Hinges are often used in pairs to create restrained expansion joints for large single plane lateral movements. See the movements and pressure thrust FAQs for definitions. For technical assistance please contact us or use our Live Chat facility.

A. A pressure balanced design uses an additional bellows to provide an equal and opposite reaction force to the pressure thrust. It’s typically used to allow axial movement but not subject the piping system to the pressure thrust force. See the movements and pressure thrust FAQs for definitions. For technical assistance please contact us or use our Live Chat facility.

A. Elaflex rubber expansion bellows (joints) are high-quality rubber joints used extensively in piping systems in the UK and worldwide to join piping systems, manage pressure and movement within the system caused by changes in pressure, materials or temperatures in the system.

A. B31.3 is the ANSI process piping specification frequently applied to industrial, petrochemical and refinery piping systems. Appendix X contains a version of the EJMA metal bellows calculation which uses a different fatigue curve to EJMA. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. EN14917 is a recent EN harmonised standard for metal bellows calculation which is based EJMA. For technical assistance contact us or use our Live Chat facility.

A. ISO 10380 is the standard to which our metal hose is typically manufactured; it defines the physical properties of the hose, deration with temperature and movement cycles. For technical assistance please contact us or use the Live Chat link on this page.

A. Hose braid is a woven wire mesh which encases the metal hose. It adds greatly to the pressure retaining capability of the hose and for very high pressure applications we use a double braid. The braid stops the hose growing in length under pressure and also helps prevent mechanical damage to the convoluted core. For technical assistance please contact us or use our Live Chat facility.

A. As materials get hotter their mechanical properties – strength – tend to decrease. This has to be taken into account when stating a pressure rating for a metal hose; the pressure rating decreases with increasing temperature. For technical assistance contact us or use our Live Chat facility.

A. Two movements must be avoided in the installation : torsion and axial movement. Torsion can result from many apparently acceptable hose installations and will reduce the life of the hose considerably. Axial extension for a braided hose assembly is impossible as the braid prevents the hose getting longer. Axial compression is also to be avoided wherever possible. Generally, lateral and loop installations are the most advantageous. Please refer to the Downloads section on our website. For technical assistance please contact us or use our Live Chat facility.

A. FlexEJ metal expansion joints for HVAC are stocked in up to 2 standard lengths for each type. Industrial configurable metal expansion joints have a range of length for each size which can be chosen at order. Manufactured to order metal expansion joints can be manufactured to any desired length greater than the minimum length required for the design movements. You can use the bellows finder to find the most suitable product. For technical assistance please contact us or use our Live Chat facility.
A. Engineered metal bellows can be manufactured from any high ductility metal. The material selection is normally based on either high temperature strength or corrosion resistance. The most frequently used materials are stainless steel 304 / 321 / 316 , high nickel alloys 625 / 825, titanium and Duplex. The pipe ends for the expansion joint are often manufactured from a less costly material than the bellows – carbon steel or CrMo for example – but frequently Stainless Steel is specified. For technical assistance please contact us or use our Live Chat facility.

A. Metal hose is available in Stainless Steel 304, 321, 316, Alloy 625, Monel and Hastelloy. It may be possible to meet requirements for other specific grades and materials but this will depend on volume and the suitability of the material to be formed. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Metal hose assemblies can operate from full vacuum to over 200 Barg. The actual rating depends on the temperature, material, diameter and braid – we can quickly advise what is possible for your application. For technical assistance contact us or use our Live Chat facility.
A. FlexEJ metal expansion joints for HVAC are rated: flanged -16 Barg, copper ended MRCA and union ended MRUA – 6 Barg. The pressure rating depends on the material, diameter and design temperature of the bellows. For engineered metal expansion joints we can normally meet any requirement. For technical assistance please contact us or use our Live Chat facility.
A. Elaflex rubber bellows are typically rated 16 Barg at 50 DegC up to DN400 decreasing to 6 Barg at 100 DegC for DN1000; please refer to the individual product rating information for each type which can be found in the brochure or click on the Range tab on any rubber bellows page. The pressure rating depends on the material, diameter and design temperature of the bellows; for engineered rubber expansion joints we can normally meet any reasonable requirement. For technical assistance please contact us or use our Live Chat facility.
A. Metal hose assemblies can operate with media temperatures from cryogenic to over 550 deg C. For technical assistance contact us or use our Live Chat facility.

A. FlexEJ metal expansion joints for HVAC are rated for between 90 to 300 DegC depending on type. Engineered metal expansion joints can be designed for flowing media temperatures up to 800 DegC and above, the bellows metal temperature is controlled to not normally exceed 400 Deg C by the internal liner and insulation design. For technical assistance please contact us or use our Live Chat facility.

A. The temperature rating depends on the expansion joint material and the expected lifetime of the bellows. Elaflex rubber bellows are typically rated up to 100 DegC (130 DegC for the DIN4809 DoubleRed Rotex type). Engineered rubber expansion joints can be rated up to 180 DegC. For technical assistance please contact us or use our Live Chat facility.

Technical - Pressure Vessels

A. PED is the Pressure Equipment Directive which applies to any pressurised equipment used in the EU. FlexEJ is accredited to ISO9001:2008 and complies with the requirements of module(s) D1, E1 & H of Annexe III of the Pressure Equipment Directive 97/23/EC and Schedule 4 of the UK Pressure Equipment Regulations 1999 (SI 2001).

Following Brexit the Pressure Equipment Directive – PED (with CE marking) became the The Pressure Equipment (Safety) Regulations – PE(S)R (with UKCA marking).

Currently the requirements of PE(S)R are essentially the same as the PED.

For technical assistance contact us or use our Live Chat facility.

A. The pressure vessel design code will stipulate the minimum certification and test requirements. These can then be augmented by customer specifications – typically we can meet all these requirements. The certification required and applicable specifications must be agreed prior to order placement. For technical assistance contact us or use our Live Chat facility.
A. ASME BPVC Section VIII – Rules for Construction of Pressure Vessels, is a standard FlexEJ uses to design pressure vessels. For technical assistance contact us or use our Live Chat facility.
“A. EN13445, Unfired Pressure Vessels, is a standard FlexEJ uses to design pressure vessels. It is harmonised under the PED. For technical assistance please contact us or use our Live Chat facility.”

A. We can work with most weldable high strength metals – typically Carbon Steel, CrMo, Stainless Steel, Titanium, Duplex Stainless Steel. For technical assistance please contact us or use the LIVE CHAT link on this page.