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What elastomeric lining material is appropriate for what service?

Rubber Types

 

Rubber selection can be intimidating as there are a number of engineered high performance linings which can have several different applications. I will list a few different elastomers and durometers as a general guideline.

There can be many different formulations of the compounds listed below with different physical properties than what is listed.

 

Soft Natural Rubber, 30-60 Duro Shore A, Temp Limit 160 Deg F, Resistance to Hydrocarbons Poor

Typical Uses: Acid Storage depending on concentration, Transportation equipment, Abrasive Services, Sulphur dioxide scrubbers.

Semi Hard Natural Rubber, 80-85 Duro Shore A,  Temp Limit 180 Deg F, Resistance to Hydrocarbons-Fair

Typical Uses: Chemical Processing and Plating

Hard Natural Rubber, 90-100 Duro Shore A, Temp Limit 200 Deg F, Resistance to Hydrocarbons-Fair

Typical Uses: Chemical Processing, High temperature nickel-copper plating, steel pickling, vacuum service.

Graphite Loaded Hard Rubber, 90-100 Duro Shore A, Temp Limit 212 Deg F, Resistance to Hydrocarbons-Fair

Typical Uses: Special lining for wet chlorine gas, in chlorine cells and associated equipment. High wear applications.

Three-ply (Soft, Hard, Soft) 40-50 Duro Shore A, Temp Limit 230 Deg F, Resistance to Hydrocarbons-Fair

Typical Uses:Steel pickling lines, Phosphoric Acid

Neoprene 40-70 Duro Shore A, Temp Limit 230 Deg F, Resistance to Hydrocarbons-Very Good

Typical Uses: Chemical or abrasive services with oil present, best for strong bases, good weather resistance, fire retardant.

Nitrile, 60-90 Duro Shore A, Temp Limits 200 Deg F, Resistance to Hydrocarbons-Excellent

Typical Uses: Aliphatic hydrocarbons, kerosene, animal, vegetable and mineral oils.

Butyl, 50-75 Duro Shore A, Temp Limits 225 Deg F, Resistance to Hydrocarbons-Fair

Typical Uses: Oxidizing acids, 70 percent hydrofluoric acids, super phosphoric acid, best water resistance, good for alternative service.

Chlorobutyl, 40-60 Duro Shore A, Temp Limits 200 Deg F, Resistance to Hydrocarbons-Fair

Typical Uses: Much the same as butyl but easier to apply and faster curing, sulfur dioxide scrubbers.

EPDM, 40-60 Duro Shore A, Temp Limits 180 Deg F, Resistance to Hydrocarbons-Poor

Typical Uses: Hypochlorite bleach, ozone and weather resistant.

 

Feel free to ask about applications and we can suggest compounds.

 

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Rubber Lined Piping & Engineering Manufacturing Procurement Process Challenges

EPC

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.