Inspection of Rubber Lined Vessels

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An inspection of a rubber lined vessel should be conducted once per year and never delayed. A close check should be maintained on operating procedures and conditions at all times. If a problem is going to occur with a rubber lining, generally it will happen within the first 3 months of service, which is why it is important to check a lined vessel after the first 3 months of service.
This is likely to be true whether the problem is caused by workmanship or by misapplication of material choice.
In some cases, the solution for which the tanks were originally lined for will have little detrimental effects on the rubber while the increase of a few percentage points in the service condition (added heat, less of more concentration, introduction of new chemical) may have a definite deteriorating effect of the rubber.
The tank must be clean, degassed, and dried before a proper inspection can be made.

A full visual inspection should be conducted, being aware of:
– Any loose seams
– Blisters
– Cracks
– Cuts
– De-lamination of the sheet surface
– Discoloration or suspicious areas

Notes of the date of the inspection should be entered within a log book which is kept on each rubber lined tank and should be updated each time the tank is inspected. The areas which were described as suspicious on the previous should be identified by some means of a reference of a location and rechecked with each additional inspection.
***Note: On entering a rubber lined tank, workmen MUST wear smooth sole shoes (no contamination is acceptable) and be very cautious not to drop sharp or heavy tools onto the lining or place hot electrical lights against the rubber linings. Ladders MUST have padded feet (both top and bottom) and placed gently inside the tank.

Any questions on inspections of rubber lined vessels or repair procedures please consult



Buck Meadows / Rubber Technologist

RubberSource at 519-620-4440.


Victaulic XL Fittings vs Additional Rubber on Elbow Extrados


Victaulic XL Fittings vs Additional Rubber on Elbow Extrados

Victaulic has come up with an interesting way to increase the longevity of fittings for mining and wear applications. For those of you who haven’t hear yet, the concept is to produce a larger ID fitting in order to add more rubber in the critical fittings, enabling your fittings to last longer. These fittings will than mate up to your standard sized ID, OD pipe.  Using a stepped XL coupling it bolts up to your existing pipe with the same ease of all 07 and 77 couplings. The ID of the thicker lined fittings matches up perfectly to your thinner lined pipe.

The majority of wear occurs in changes in direction. Elbows are particularly vulnerable to wear do to this fact. By increasing the rubber in the fittings from 1/4″ thick rubber to 1/2″ rubber you get two benefits. You get a thicker wear sub-straight and a better cushion for the forces on the liner. The result is a significant increase in lifespan from these fittings.

The down side to these fittings is that you can no longer use the standard 77 or 07 couplings in your system. You will need to get the stepped XL couplings. Since these fittings are unique to rubber lined systems the availability and lead time on these components can be a challenge.

Traditionally the way to increase the life in your elbows is to add an additional layer of 1/4″ rubber on the extrados of the elbow. This created the 1/2″ of rubber desired. This allows users to keep their existing couplings and adds longenvity to the elbows..

The downside to this type of additional wear material is the transitions are not always made the same. Depending on the rubber liner installer, you can get  various transitions in the rubber, some better than others. If a bad transition is made in the rubber, you can get an undesired turbulent effect. This will result in eddy currents in the elbows and fittings and this effect will prematurely wear out the liner.

Victaulic has created a good system which addresses the additional material required in high wear situations. It is an effective way to increase the life span of your fittings. The ID’s of the fittings and pipe having no transitions which ensures no unintended premature wear.



Celebrating 1 Year for RubberLining.org

1 Year Celebration

Celebrating 1 year for RubberLining.org

We have had a fun year blogging about rubber lining and the associated disciplines.

More and more followers have been coming to visit our blog every month, averaging 300+ views per month. We are happy and able to help with any of the industries technical questions. If we don’t know the answer we are definitely able to point people in the right direction.

We want to send out a special thanks to Rubber Source for contributing articles to this open forum of rubber knowledge. If any of our readers feel inclined to submit a rubber lining industry articles, we would be happy to post them. We plan on having many more years of blogging to share in our industry specific knowledge. The more people who get involved in sharing rubber lining industry knowledge the better the industry will be.

Stay tuned for more articles on rubber lining.

Thanks for following along.

from the Rubberlining.org team.


Bends and Rubber Lining



Bends and Rubber Lining

The use of bends in a designed piping system is critical to managing wear in piping directional changes.

In short the longer you can make the directional transition, the less wear you will ultimately have in your elbow. Induction bent elbows provide engineers and designers an infinite degree of adjustment and allows the elbow to have any sweep dia,  limited only by the sweeping arm of the induction bending machine.

Although there are very little limitation of what can be fabricated as an elbow, lining these elbows with rubber can be a challenge.

Here are some general rules of thumb.

Positive: Larger diameters elbows are easier to line as you can reach the inside to stitch and work out possible air pockets.

Negative: Large diameter tubes are very heavy and hard to manage, sometimes difficult not to create wrinkles

Negative: Small diameter long swept bends are challenging as you cannot manually adjust the tube in the swept section. Difficult to stitch in corners.

Negative Small long swept bends can hide bubbles and wrinkles as they can be hidden in the inside radius which is impossible to see with the naked eye.

Positive: Small diameter tubes are generally easy to handle.

Thick liners in small diameter bends are difficult, due to the tube not wanting to turn the corner and kinking when folded in half. The liner has tendencies to create large wrinkles.

New trends is to have thick liners in pipe and elbows. Engineers are using the additional rubber thickness in order to match flow calculations and standardize pipe size. An example of this would be using a 30″ dia. pipe and lining it with 2″rubber. The engineering design recommended 28″ pipe for the flow. But 28″ pipe is not common  and 28″ flanges and valves are not commonly stocked and are very expensive. Using 2″ rubber would accomplish the reduction in interior diameter.

Other times the belief is that a thicker liner will make the elbow last longer, this is inaccurate. If using the correct compound for the fluid with particle size and flow taken into consideration than 1/2” rubber sub-straight is ample for best performance.

Lining with 2″ thick material is extremely in-practical. The weight of the tube would exceed the tear strength of the silk required to pull the tube through the elbow. The tube would weight in the area of 700 lbs. The other challenge with such a thick liner, the sag created in the material during the vulcanization process will create an uneven liner. The top of the part would thin and the lower section would increase dramatically. An uneven liner generally created uneven wear.

From a designing perspective, 3D bends should generally have a minimum 1D tangent. Anything less and the end of the pipe will result in an elliptical form. An elliptical end will create challenges with the termination, flanges and grooved ends. This generally doesn’t affect rubber lining but 1D tangents are good design practices.

 Pro Tip.

-Although 6 D bends are great for wear, the most common swept bend ordered are 3D 45’s and 90’s. These are common and stock in most location have a 1D tangent. Even if the site has a 1 deg slope try to standardize all bends to normal standard angles for ease of replacement and interchangeability.

-3D Bends 8″ and below 1/4″ liners

-3D Bends above 8″ 1/2″ Liners.

-3D Bends above 16″ if required 1″ liners are possible

-On cyclone under-flows where the material if very coarse like 3’/4″ ,minus allow for the longest possible Radius such as a 5D or 6D elbow.



Rubber Lined Piping & Engineering Manufacturing Procurement Process Challenges


Doing a large project for engineering firms can be rewarding and challenging depending on the contract at the same time. Here are some of the process challenges with rubber lined piping and piping projects in general.

The most common way to price many short lead, large scope projects is to bid a Bill of Material. These BOM’s are generally generated form a snapshot of their CAD system model. The CAD bill of materials unfortunate provides the first challenge such as how to price 10,000 feet of pipe when you don’t know the individual lengths? How many termination are there, how many branches are there, supports etc…? The descriptions of the piping will say rubber lined grooved. So to determine the quantities of grooves you must sometimes estimate based on the coupling count.

Some of these challenges have been overcome by providing welding rates, cutting rates, branch rates etc… This method of pricing does not provide the purchasing groups a clear cost on the project. As many of the welds and cuts do not get rolled up or counted into the price. The preferred alternative is to price a- la cart. This style of pricing would mean that any flange price listed for example in the BOM would include all the shop processes required to fasten a flange for example to any piece in the system. This provides a transparent all in fabrication price.

Assuming your prices are competitive and you won the contract, the next challenge is that generally the fabrication drawings are not complete. Hopefully the purchasing people will allow you to purchase the BOM as it stands, as waiting for drawings can delay projects, while the drawings are being completed you can purchase and stage your materials for fabrication. Next arrives the drawings and they pose their own problems as discussed in my blog on cad challenges.

Now you fabricate your rubber lined piping. When you ship your project to site you are not shipping flanges pipe and a branch separately. You are shipping a spool that contains all the materials listed in the BOM. Reconciling the original PO is extremely difficult as the original PO is based on a BOM. Depending on the purchasing team a backup document containing the price breakout of the spool may becomes a useful tool to reconcile the billing on the spool i n order to eventually consolidate the project purchase order at the ends

Keeping these interesting challenges in mind and discussing the challenges with an agreement ahead of time, before the issue of a purchase order will ensures a smooth trouble free contract.



Rubber Lined Piping Systems and your Cad System


Modern Cad systems can be problematic for rubber liners….

1 Cad people may not take into account the rubber gasket on the face.

Normally when an engineer lays out the piping system they choose many different ways for the software to dimension the Isometric.

Long run dimensioning – Dimensioning from intersection to intersection, this is ok if you let the fabricator interpret the spool lengths. Generally the pipe lengths get indicated but the rubber lined face gaskets are not taken into account, groove type gaps or the fitting dimension are incorrectly setup. The other common mistake to this style of dimensioning is that the travel exceeds the physical manufacturing limitation of the spools in between.

Spool dimensioning -Dimensioning to the center of all the joints- This is by far the best method if the model is setup correctly. Grooves should be modeled not just specified, as the tolerance of this should be taken into account (1/8″ rubber on the face of the groove as well). The biggest challenge becomes when people use stock grooved libraries for non rubber lined product for a rubber lining system. The addition of the face rubber increases the fitting dimensions.

2 Descriptive modelling

As most modern advanced Cad systems such as Bentley, Aviva, Integraph or Microstation are very ridged and are provided with a standard parts library. For example many rubber lined systems end up being a coupled system. When using auto routing for piping, rules are set for spool lengths and gaps. A common cheat is to describe the piping as piping with grooves and to download the spool separations to the manufacturing. The result is that most spools in this case will have to be redrawn by the manufacturer as opposed to processed using Spoolgen for example. The redrawn spools may not always conform to the design dimensions making drawing checking and receiving of final product very difficult.

3 Libraries built for a steel only system.

All cad systems in the market are built to accommodate steel fabricated systems. So there are always compromises when it comes to descriptions and dimensions. As a rubber lining supplier it is very cost prohibitive to create libraries for all the engineering systems. Currently  some coupling system companies have up to 23 different software catalogues built so that engineers can use their products.

4 Specifications do not always contain the compounds or thicknesses.

When processing Isometrics a specification a line class is usually provided. Some time these are very well laid out for rubber. Other times it is a combination of pipe sizes, service and line class that will determine the lining. The lining information is often not contained on the Isometric itself. Depending on your cad team this can be a difficult item to interpret from the information provided.


The sooner you can get involved in a project the better. Working with the engineering firms, understanding their challenges and concerns will help you find common grounds. Working with both the EPCM and end users will reduce processing errors, reduce the overall project lead times and cost.



Storing Rubber Lined Equipment




1.   Rubber linings should never be exposed to direct sunlight or direct outdoor weathering, for periods longer than a few days.   All other linings should be protected from sunlight. If no other alternatives are possible, linings should be periodically painted with Age Guard.



1.   If possible, store in shaded areas away from direct sun exposure.

2.   Paint outside of tanks with aluminum or white paint, or cover with a tarpaulin.

3.   Closed tanks should be kept ventilated.

4.   Tanks to be stored for long periods after having been in service, should be partially filled with a diluted solution of the chemical they were designed to contain (a 1-3% concentration probably will be sufficient).

5.    For piping, the ends to be capped at all times before going to service.  Helps protect against the weather and damage that may occur on site



1.   Equipment should be protected as much as possible from the elements by covering with tarpaulins, erecting temporary shelters, etc.

2.   Tanks containing solutions must be emptied if temperatures drop below the freezing point (of the solution contained therein).

3.   Equipment should be handled very carefully and protected from subjection to external forces (sudden blows, flexing, twisting, etc.). Sudden temperature changes also are to be avoided. These precautions are most important for linings with a hard durometer.



1.   Idle or standby equipment (especially semi-hard lined) should be protected against excessive drying out and temperature changes. The best way to accomplish this is to fill the tanks with a 1-3% solution of acid, preferably H2S04, and hold at ambient temperature. This will help keep the lining more flexible and minimize the expansion and contraction problem as well as decrease the possibility of thermal shock when the equipment is put back into service.

2.   If the diluted solution is not optioned, then apply Age Guard to the rubber linings once per year the lined equipment is idle.***Note: All idle equipment should be inspected prior to being put into service.


Any questions please contact RubberSource @ 519-830-0546 / buck@rubbersource.ca


Buck Meadows / Rubber Technologist

Technical Sales Manager





How to compare rubber compounds for slurry applications.


Rubber specifications are confusing and some of the properties described in some specification sheet do not help evaluate the wear characteristics of the compound.

In fact most of the time the important lab tests, which tell you how well a rubber will perform in a slurry application are left out.

Specification sheets contain many characteristics which are elemental by definition. In other words the fact that the rubber is tan in color has no relevance to the actual wear “the undesirable mechanical removal of material in fine particle from from the surface.”

Here are some of the common specification criteria and their relevance.

Durometer: (Elemental Property)

In a slurry wear application the fact that a rubber is softter than another may indicate that it may be perfom better or worst but that would be opinion. Harder compounds generally perform better under cut and chip situations but there is a lab test for cut and chip as well as wet sliding abrasion. Durometer is not really the deciding factor. This rubber just happens to be a given duro shore A.

Tensile Strength: (Elemental Property)

Tensile strength is very useful when comparing rubberized tracks and track pads for tanks. As the ability not to rip apart is important. When comparing an elastomeric lining which is adhered to a steel sub-straight it’s tensile strengthen is not relevant factor in this application.

Ultimate Elongation: (Elemental Property)

Going back to my previous example when a snowmobile takes off  the ultimate elongation is very important so that engineers and designers can calculate if this track will perform correctly. In a rubber lined wear application this factor is not relevant. It will never achieve it’s ultimate elongation adhered to a metal sub-straight.

Specific Gravity: (Elemental Property)

This is the actual density of the product. In the olden days the buoyancy of rubber was a good indicator of how many rubber fillers were in the product. Floating rubber was regarded as good rubber. Dense rubber was thought to have more clay which would adversely affected it’s wear performance. This day and age with material sciences helping to improve material quality, adders like carbon is common. Carbon increases wear characteristics in some cases. Therefore the specific gravity is simply that, what it’s density is. Not a good wear performance indicator.


Performance properties are “Real factors which can be tested and directly speak to the wear performance in a slurry application.”


Cut and Chip: (Wear Performance Property)

Cut and chip is a test performed in a lab where you can accurately compare compounds and find which is the best in a cut and chip application. This is completely relevant when you are trying to increase the longevity of a liner in a slurry application. This was a test devised by BF Goodrich in order to evaluate how good the tires would perform on the road. A very good indicator of wear life.

Wet Abrasion: (Wear Performance Property)

A test to determine the exact resistance in wet abrasion. It’s a sliding plate that cycles on the rubber in a container of a known wear slurry and the removal of the material is then measured to determine is wear performance characteristics. This is very relevant to wet sliding abrasion test to determine the rubber wear.

Water Resistance: (Wear Performance Property)

Also known as the percentage of swell. The reason this is important is the amount of swell will adversely affect wear within certain services such as acid. The more a rubber will swell the less it will perform in that situation.

Resilience:(Wear Performance Property)

The ability to return to it’s original shape is a huge factor in determining if this rubber will be suitable for wear. The more resilient the better the rubber will perform in a slurry application.

Tear (Die C):(Wear Performance Property)

This is another important performance criteria as the ability for the rubber to hang on to the straightaway is important. This is a relevant value when considering rubber for slurry wear applications.


Rubbers with high Cut an Chip resistance and Wet Abrasion resistance will perform better in wet slurry application. Elemental properties such as density are interesting and mater of fact but should not be deciding factors when choosing rubber compounds for wear applications.





General Call for Rubber Lining Industry Suppliers Articles!


Rubber Lining.org is a site dedicated to being the repository of knowledge for the rubber lining industry.

We welcome articles from professionals in the rubber supply, rubber  lining, piping, engineering and wear industry. We will publish all articles related to rubber lining and associated information as long as they are written by rubber lining industry professionals who wish to contribute to this knowledge base and given that the articles are non-partisan.

If your company contributes an article you will get credit for the information as well as get listed under one of the vendor tabs at no cost.
If you wish to submit an article please e-mail it to.




What is Rubberlining.org

Rubberlining.org is a web site dedicated to providing information about the world of rubber lining.  We will touch on subjects and factors that affect wear, the best methods for applying rubber, what types of compounds are best for the applications.