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Assessment life by cycle on FRP Pipeline - ASME B31.3
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(Mechanical)
(OP)
9 Feb 11 08:36I'm in the process of checking a FRP (AWWA C950 Cl. 50 ) pipeline flexibility analysis by subcontractor. I asked why he uses Stress Range Factor (See Fig. 302.3.5) f=1 for reduction of stress allowance by cycle at ASME B31.3 and his argument it's the following:Subcontractor considered a complete thermal cycle to set N in equation f = 6.0*N^(&#;0.2) &#; fm. The full cycle means, by subcontractor, is given for each plant shutdown. As the pipeline is under roof, the temperature range dominant it's fluid range (T°min &#; T°max) so he did not consider important the daily temperature difference (T°min &#; T°max) of fluid to set it as thermal cycle (N). So his calculation is if the plant has an operating life of 26 years, considers 2 plant shutdowns per year then:N = 2 * 26 = 52 cycles < &#; f = 1.My doubts is whether is it right, for FRP to set N = 52 or should he takes the daily temperature difference (T°min &#; T°max) of fluid to calculate N?Temperatures data:T° min= 50° F (Fluid Temperature)T°max = 68° F (Fluid Temperature)T°ambient = 5°/77° FAny clarification would be greatly appreciated.Drakkkko
Replies continue below
(Petroleum)
9 Feb 11 11:19It would appear to be correct. You don't have thermal cycles unless the temperature goes up, then comes down, or v/v.
(Industrial)
9 Feb 11 12:03How often does ambient go below 50°F? If it is only during Shutdowns, that will probably only once per year, unless this is on the North Slope. It is just not that cold at both ends of any 6-month period, most locations. A 'true' temperature cycle is a fairly rapid swing of more than 10°/hr or 25°F/8-hrs.
Thus, I concurr with
BigInch
(Mechanical)
9 Feb 11 18:12Reference Fluid cooling water FRP:
Requirement of the ISO CODE
Use FRP Flexibilites: such as BS OR UK00A flexibility factor of 1.0.
Use FRP SIF:If checked and any code other than specifically addressing FRP BS OR UK00A is in effect, all fitting will receive fixed SIF of 2.3
this reference is 26 pages.
Steve
(Mechanical)
9 Feb 11 19:43BS is a withdrawn Code of Practice. It also has limitations on size and pressure rating. It could be used as a guide but not to be relied upon in any contractual matter.ISO is a good reference that is current but cross referencing out of date documents is a problem.Average wall temperature could be based on indoor temperature variation and fluid temperature variation. It is not going to be > ambient temperature but will be < than fluid temperature.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
(Mechanical)
9 Feb 11 22:51stanier (Mechanical) Thank you!!
My reference was
COADE CAESAR II Seminar JOB: COOLH20 Fiberglass Cooling Water System Total: 26 pages
Steve
2
T(Mechanical)
16 Feb 11 11:18Using B31.3 code to analyze the flexibility of the FRP piping may not be the right one. The FRP piping design should be strictly followed the manufacturing guideline, simply because each FRP supplier has its own method of deriving the pipe properties. If this info is not available at time of performing the analysis, ISO is the one to be considered. In short, The flexibilities and stresses of the FRP piping system should be within the "design envelop" recommended in the ISO. Once the "design envelop" is met the analysis is done. Thermal fatique is not required per ISO . This is only my 2-cents and hope it answers your questions. Good luck!
(Mechanical)
16 Feb 11 17:59I did come across some work by Norska on the SIF valvues of FRP fittings. These fittings are commonly hand laid up, particularly for the larger sizes. The wall thickness is uncontrolled and thus the flexibility expected does not eventuate. It would appear the manufacturers think thicker is better.One project I was involved in actually measured the strain at bends and then decided to reinforce the fittings, or not.FRP is such a nightmare contractually for in plant product. You have to lock into a supplier so you can do the design. This leaves you exposed to cost blow out. You need to ascertain the prime cost of fittings beforehand. Estimate the quantum and cost the job. Then you can enter into an alliance type contract. Always insist on open book so you can see the actual costs.Be wary of the negative pressure capability of FRP. FRP products do not always meet full vacuum criteria. If you have pump trips then your waterhammer analysis will tell you if column separation is going to occur and what your negative pressures are likely to be.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
(Mechanical)
(OP)
25 Feb 11 07:23I would like to thank everyone which collaborated and helped me. The project wich I'm working for it's located in Chile North (Antofagasta city is a reference for location).
I have one last question specific to user Duwe6. You talked about a simple criteria to determinate a 'true' temperature cycle (more than 10°/hr or 25°F/8-hrs.), where that rule come from? for your own experience ? from ASTM / BS standar code ? I thinking to use that criteria but of course I need a documented support.
(Industrial)
25 Feb 11 11:08drakko
, it was based on experience & eng. judgment. There is very, very little stress from a slow change in temperature -- all the pipe and its contents stay at the same temperature.stanier
brought up, pump trips and the associated water hammer are also a substantial load, overshadowing temperature differentials.(Mechanical)
25 Feb 11 12:29Case close
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Please note, this is a technical article describing the steps to a successful FRP joint installation. If you are looking for information on RPS Field Service installation, please go here.
In our previous article, we looked at basic principles for designing and fabricating supports for an frp piping system. In this, our final article in the series, we are going to take a look at installation of FRP piping systems.
While installation might not typically be considered as part of the pipe system design, it is such an important part of a successful system that we believe it needs to be emphasized here. Without doubt, more issues arise in FRP piping systems due to improper installation than due to any other single cause. There are a number of steps that must be followed to provide assurance that problems won&#;t arise later, and also to comply with the requirements of ASME NM.21.
These steps include
Let&#;s look at these steps in more detail.
For any FRP piping system, the manufacturer should prepare jointing instructions that apply to the specific piping system of interest. This would include general instructions that apply to almost any FRP jointing operation, and should also include specific instructions for each type of joint and each size of pipe of interest. General instructions would typically address issues such as safety, required tooling, appropriate ambient conditions, surface preparations, etc. Specific instructions would include laminate sequences and reinforcement dimensions. Collectively, these instructions are referred to as the Bonding Procedure Specifications or &#;BPS&#;. This is the terminology used in the ASME piping codes, i.e. B31.1 &#;Power Piping&#; and B31.3 &#;Process Piping&#;, as well as the new ASME standard for FRP piping, NM.21, and is completely analogous to the Welding Procedure Specifications used for metallic piping systems.
If you want to learn more, please visit our website GFRP Piping.
While all of the instructions must be followed for proper jointing, it is worthwhile emphasizing the need for proper surface preparation. It is probably safe to say that no single step in the jointing process is more important than the surface preparation. If this is not done properly, there is a very good chance there will be problems later.
Once the BPS has been prepared it needs to be qualified. There are a number of differences between B31.1 and B31.3 and NM.2 with respect to the requirements for procedure qualification, but in all cases, a sample spool must be assembled, examined for quality, and pressure tested. In the case of B31.3 and NM.2, the test spool must include each type of joint to be qualified, and the spool must survive a pressure test of 3 times the design pressure for 1 hour. A record is prepared to document the specifics of the jointing process and the results of the qualification testing. This record is referred to as the Procedure Qualification Record, or &#;PQR&#;.
Once the BPS has been qualified, the bonders themselves must be qualified to make joints using that procedure. The first step in this process is to ensure the bonders are properly trained. This would typically include a 2 &#; 3 day training course by the pipe manufacturer, and would address all aspects of bonding from proper storage and handling of materials, to joint preparation, and laminating techniques. RPS regularly conducts these types of courses for 3rd party installation teams and owners&#; maintenance staff. RPS can also provide further installation services including quality control of jointing operations, supervision of installation crews, and full responsibility of jointing and installation activities.
After a bonder has received appropriate training for the type of joint to be made, he/she assembles a similar test spool to that used for the procedure qualification. Again, the spool has to be examined for quality and pressure tested. The same requirements apply for the bonder qualification as for the procedure qualification. Each qualified bonder is assigned a unique identifier so that each joint made by that bonder can be traced to the bonder. A bonder remains qualified to the procedure for as long as they continue to make joints using that procedure. A bonder would have to be re-qualified if he/she did not use the procedure for more than 6 months, or if there were any reason to question the bonder&#;s ability make joints to the BPS.
A record is prepared to document the results of the bonder qualification. This record is referred to as the Bonder Qualification Record, or &#;BQR&#;.
After examination of the completed joints, the final step in ensuring the joints have been properly made is the performance of a hydrotest. ASME B31.1, B31.3, and NM.2 all require piping systems to be tested prior to being put into service. This is usually accomplished with a hydrotest at a pressure of 1.33 to 1.5 times the design pressure for the system. The pressure is held for a minimum of 10 minutes after which the joints must be examined for leaks.
Bonding operations for successful FRP pipe installation are not difficult to do well. But it is necessary to adhere to the steps discussed above to provide assurance that joint issues won&#;t arise later.
This is the last article in the series. If you have any questions, or if your team would like to arrange a Lunch and Learn with our Engineers, please contact us.
1 ASME NM.2- &#;Glass-Fiber-Reinforced Thermosetting-Resin Piping Systems&#;
Previous article in the series: Considerations for Proper Support of FRP Piping
See Resources to learn more about choosing FRP and dual laminate as your material of construction.
Numerous industries use FRP piping today, including oil and gas, power plants, chemical processing, pulp and paper, and water/wastewater.
Fiberglass Reinforced Thermosetting Plastic pipe (FRP) is manufactured with a winding process that combines thermosetting epoxy resins reinforced with continuous glass fibers. The resins provide superior chemical resistance capabilities, while the fiber reinforcement gives the pipe exceptional mechanical strength. Fillers and dyes can also be added to the composite material.
FRP pipe is not the same as other plastic pipe such as polyvinyl chloride (PVC) or polyethylene. The composite of filament reinforcement and epoxy resins result in a much stronger, light weight pipe.
FRP pipe comes in sizes from one to 144 inches diameter. FRP pipe offers much flexibility and potential for customizing pipe for various industries.
FRP has been around since the late &#;s and was primarily used in the oil industry at that time. In the late &#;s, as larger pipe diameters became available, the chemical process industry and pulp bleaching processes started using FRP. Its corrosion resistance and high conveying capacity made FRP especially attractive.
In , the American Society for Testing and Materials (ASTM) published the first nationally recognized standards and test methods for FRP pipe. The American Petroleum Institute (API) published the first FRP pipe standard in . Today there are numerous standards for FRP pipe, from ASTM, American Society of Mechanical Engineers (ASME), International Organization for Standardization (ISO), American Water Works Association (AWWA) and other associations.
In the &#;s FRP municipal water and wastewater facilities began using FRP piping due to its durability and strength. FRP&#;s corrosion resistance eliminates the need for special pipe linings as well.
Coal-fired power plants began adding scrubbers to remove sulfur dioxide in the &#;s. Scrubbers convert the sulfur dioxide into a fluid or slurry-type substance pumped through FRP piping. Waste streams at the back end of power plants, such as ash ponds and water/wastewater systems also utilize FRP in their piping systems.
The low maintenance and life cycle cost of FRP compares favorably to stainless steel and other exotic metal piping for many industries today. FRP is also resistant to wear, corrosion and has a high strength-to-weight ratio, and FRP&#;s light weight makes it easier and less costly to transport.
Continuous improvements in the number and type of resins, combined with various fillers and dyes have broadened the use of FRP pipe even more. Resin systems and reinforcements can be tailored for an application depending on corrosivity, temperature, abrasiveness, and other aspects of the matrix and environment.
Expansion joints are flexible connectors used in piping systems of nearly all industries. They allow for movement within a piping system that occurs due to changes in temperature or pressure. They can also reduce noise and vibration. Expansion joints come in a wide variety of types and materials.
Using the wrong expansion joint in a piping system can reduce the life of the joint and have potentially disastrous consequences if the joint fails. Selecting the proper expansion joints for a specific project is critical to optimizing the life of the joints, reducing downtime, and protecting employees. The variety of options makes it even more important to spend time selecting the proper joint for each application and piping system.
FRP piping has special characteristics that must be considered when determining which expansion joints to include. Below are some common pitfalls to watch out for when selecting expansion joints for FRP systems.
The combination of lower strength pipe and large thermal expansion must factor into the expansion joint selection. Expansion joints must be the &#;weak link&#; in the piping system to provide the needed movement and flexibility. Thus, the expansion joint cannot be stronger than the pump, pipe, or pipe flange. Expansion joints used in FRP piping systems need to be lower in stiffness than those used in steel piping systems.
The forces developed during a temperature change are relatively small in FRP piping as compared metal piping systems. Therefore, expansion joints specified for FRP systems must be activated by low forces.
The engineer must understand the &#;allowables&#; for stiffness and the amount of force needed to compress the expansion joint versus the flange itself. The allowable activation force for expansion joints depends on both the thermal forces developed and support spacing. Supports must be the type that prevent lateral movement.
In FRP piping systems, expansion joints may also need lower spring rates to compress, extend or laterally offset pipe movement. The required activation force for FRP piping needs to be smaller than would normally be expected for steel piping.
A common pitfall occurs when the wrong expansion joints are specified because insufficient data was obtained prior to design. This includes the &#;STAMPED&#; criteria below, as well as the range of thermal movement and an analysis of stresses on the pipe.
The more information the expansion joint supplier has, the more likely the proper joint will be provided.
Pipe runs are often long, so stiffness and movement must be a consideration for expansion joints during design. Knowing the &#;STAMPED&#; criteria is essential to preventing joint failure and optimizing life.
Size: What is the inner pipe diameter, pipe thickness, overall distance between flanges? Temperature: What is the temperature range of the media and rate of change? If the pipe is located outside, what is the ambient temperature range? Application: In which industry are the joints being used, and what type of equipment is connected? What is the process media &#; fluid, solids, gas? Acidic, basic, or neutral? Movement: What is the expected type and magnitude of movement of the pipe at specific locations? Pressure/Vacuum: What are test, operating and surge pressures within the system? End Fittings: What type and configuration are the end fittings? What drilling pattern will be needed? Delivery: How quickly are the expansion joints needed?Size: What is the inner pipe diameter, pipe thickness, overall distance between flanges? Temperature: What is the temperature range of the media and rate of change? If the pipe is located outside, what is the ambient temperature range? Application: In which industry are the joints being used, and what type of equipment is connected? What is the process media &#; fluid, solids, gas? Acidic, basic, or neutral? Movement: What is the expected type and magnitude of movement of the pipe at specific locations? Pressure/Vacuum: What are test, operating and surge pressures within the system? End Fittings: What type and configuration are the end fittings? What drilling pattern will be needed? Delivery: How quickly are the expansion joints needed?
Because FRP pipe is wound with fiberglass filaments it has different thermal expansion in the hoop and axial direction. While FRP pipe has about the same thermal expansion as steel in the hoop direction, it has about twice that of steel in the axial direction. The complete range of thermal movements in the piping system must be determined to optimize expansion joint life when using FRP pipe.
The maximum thermal expansion and contraction should be calculated to ensure the expansion joint can absorb the full range of movement. Calculate temperature changes for expansion by subtracting the installation temperature from the maximum design temperature. Calculate changes for contraction by subtracting the minimum design temperature from the installation temperature.
A pipe stress analysis data sheet showing the loads, movements and allowable for spring rates provides critical information needed to build the proper expansion joint. Many companies design their piping systems using computerized pipe stress analysis programs.
The selected expansion joints must be able to accommodate any motion, in either direction, which can occur in the piping system. Piping should be aligned within 1/8&#;. If offset is more consult with expansion joint provider and engineer of system for allowables. A calculated degree of preset must be completed during installation for most systems.
Collaborating with experts that have practical experience will help engineers to understand the expansion joint specifications for FRP systems. Getting technical advice can ensure the proper expansion joints are designed and installed for a specific piping system. These professionals can educate staff on ways to optimize expansion joint life and reduce costly downtime.
Proco Products, Inc. team will work closely with engineers during the design process to properly to recommend the right types and locations for expansion joints in a system or project.
Proco Products works with FRP engineering specialists at Maverick Applied Sciences to provide FRP piping forums. Proco also gives presentations on expansion joint selection, installation, and maintenance. In addition, Proco can provide a free expansion joint survey in existing systems, complete with a written report of detailed information and photos.
Proco also has a good relationship with FRP suppliers, who can provide assistance as well. Proco is affiliated with the Fluid Sealing Association, the think tank for rubber expansion joint design. where manufacturers listen to engineers and industry experts to learn about real life problems in the field and provide solutions.
Proco Product&#;s Series 230 expansion joints are used in heavy FRP chemical and power plants. These joints are available as single, double, or triple wide arches and come with open arch (for fluids) or filled arch (for solids).
The Series 230 expansion joints are available in various elastomers for FRP systems. They are especially designed to reduce the need for maintenance.
All these products absorb directional movement, vibration, noise, and shock.
Proco Products 260R series molded wide arch expansion joints are also used in FRP piping systems. These expansion joints have the lowest spring rates and forces to compress, extend or laterally offset compared to any expansion joint made today. This means they can be used with FRP pipes, pumps, valves, and tanks without fear of the expansion joint being stronger than the connecting appurtenance. They also work well in PVC and CPVC piping systems.
These joints are suitable for numerous tough applications, including those with corrosive materials chemical, petroleum, and pulp and paper facilities. They can be used in retrofitting projects where metallic hoses or expansion joints, or older designed joints were previously installed.
The 261R and 262R rubber expansion joints absorb thermal movements that occur in the piping system due to temperature changes. They dampen noise and vibration generated by mechanical equipment and reduce resulting stresses in the system downstream.
The 261R is a single molded wide-arch expansion joint and the 262R is a double molded wide-arch joint used for fluid service.
The 260R series can be supplied with EPDM and nitrile elastomers as well as others.
Proco Products, Inc. is a global company, and maintains one of the largest inventories of rubber expansion joints in the world.
Want to learn more about expansion joints in FRP piping systems? Contact us today.
FRP (Fiberglass Reinforced Plastic) pipe, as with other materials, is required to comply with the ASME B31.3 Pressure Process Piping Code. There are deficiencies in the Code relative to FRP. FRP is a unique material in that there are no established pressure-temperature ratings as there are for other materials, e.g. steel, PVC. The Code does provide rules for pressure design of components with no established ratings. However, the rules for FRP can be very confusing and ambiguous. The code provides rules for stress analysis of pipe systems but does not adequately address the unique properties of FRP. The installation and testing requirements for FRP also need to be updated. This paper will summarize the ASME Pressure Piping Code current requirements for the pressure design, stress analysis, and installation of FRP pipe in process applications (excluding gas pressure pipe and non-pressure applications). A Pipe Project Team is currently working under Task Group F of ASME B31.3 to review and revise the Code as it deals with FRP and the paper will also provide an update on the status of that review and recommended changes.
INTRODUCTION
ASME B31.3, Process Piping, contains mandatory rules for non metallic piping in Chapter VII (ASME B31.1, Power Piping, contains non-mandatory rules in Appendix III and is virtually identical to B31.3 in dealing with FRP pipe. The Code does not properly address allowable stresses for loads other than pressure. Safe and accurate design and analysis of FRP pipe systems requires a more rigorous approach than currently out lined in the code. This paper will clarify the current code requirements, identify potential deficiencies, and provide current recommendations for upgrading the B31.3 based on the work of the ASME project Team.
CURRENT CODE REQUIREMENTS
Pressure/temperature ratings
The Code allows the use of three different pressure-temperature design criteria for pipe and fittings:
1) Listed Components having established pressure-temperature ratings can be used. (Listed Components refers to components for which a standard or specification is listed in Table A326.1 of the Code. The pressure -temperature rating must be included in the standard or specification).
2) Listed Components for which design stresses have been established in accordance with the Code can be used. The Code provides a method for calculating design stress based on ultimate stresses, which have been established in accordance with standards, or specifications listed in Table A326.1 of the code. A pressure design method for calculating minimum pipe wall thickness based on the design stress is included.
3) Unlisted Components can be used if their pressure design satisfies one of the following:
a) They conform to a published specification or standard; and the designer is satisfied they are similar in composition, mechanical properties, and method of manufacture to listed components; and their pressure design satisfies the formulas for pressure design in the code.
b) The pressure design is based on calculation and verified by extensive successful experience under comparable conditions with similarly proportioned components of the same or like material.
c) The pressure design is based on calculation and verified by performance test, which takes into consideration design conditions, dynamic and creep effects, and verifies the suitability of the component for its design life.
Table A 326.1 Component Standards includes ASTM (American Society of Testing Materials), API (American Petroleum Institute), and AWWA (American Water Works Association) standards for FRP, Glass, Thermoplastic, Thermoplastic Lined Steel, and other non-metallic pipe, fittings, an
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