WARNING:
Failure to follow the installation instructions may cause premature failure and/or rupture of the unit resulting in property damage, serious personal injury, or even death.
Service Conditions
Ensure the expansion joint rating for temperature, pressure, vacuum and movements match the system requirements. Contact UIP International, Inc. for advice if system requirements exceed those of the expansion joint selected. Make sure the elastomer selected is chemically compatible with the process fluid or gas.
Alignment
Expansion joints are not typically designed to compensate for piping misalignment errors. Piping should be lined up within 1/8”. Misalignment reduces the rated movements of the expansion joint and can induce severe stress and reduce service life. Pipe guides should be installed to keep the pipe aligned and to prevent undue displacement.
Anchoring
Solid anchoring is required wherever the pipeline changes direction, and expansion joints should be located as close as possible to anchor points. If anchors are not used, the pressure thrust may cause excessive movements and damage the expansion joints.
Pipe Support
Piping must be supported so expansion joints do not carry any pipe.
Mating Flanges
Install the expansion joint against the mating pipe flanges and install bolts so that the bolt head and washer are against the retaining rings. If washers are not used, flange leakage can result–particularly at the split in the retaining rings. Flange-to-flange dimensions of the expansion joint must match the breech type opening. Make sure the mating flanges are clean and are flat-face type or no more than 1/16” raised face type. Never install expansion joints that utilized split retaining rings next to wafer type check or butterfly valves. Serious damage can result to a rubber joint of this type unless installed against full face flanges.
Tightening Bolts
Tighten bolts in stages by alternating around the flange. If the joint has integral fabric and rubber flanges, the bolts should be tight enough to make the rubber flange O.D. bulge between the retaining rings and the mating flange. Torque bolts sufficiently to assure leak-free operation at hydrostatic test pressure. Bolt torquing values are available. If the joint has metal flanges, tighten bolts only enough to achieve a seal and never tighten to the point that there is metal-to-metal contact between the joint flange and the mating flange.
Storage
Ideal storage is a warehouse with a relatively dry, cool location. Store flange face down on a pallet or wooden platform. Do not store other heavy items on top of an expansion joint. Ten-year shelf life can be expected with ideal conditions. If storage must be outdoors, joints should be placed on wooden platforms and should not be in contact with the ground. Cover with a tarpaulin.
Large Joint Handling
Do not lift with ropes or bars through the bolt holes. If lifting through the bore, use padding or a saddle to distribute the weight. Make sure cables or forklift tines do not contact the rubber. Do not let expansion joints sit vertically on the edges of the flanges for any period of time.
It is generally stated that the proper location of rubber expansion joints is close to a main anchoring point. Following the joint in the line, a pipe guide or guides should be installed to keep the pipe in line and prevent undue displacement of this line. This is the simplest application of a joint, namely, to absorb the expansion and contraction of a pipeline between fixed anchor points.
Control Units Used in Restraining the Piping System Control units may be required to limit both extension and compression movements.
Extension
Control units must be used when it is not feasible in a given structure to provide adequate anchors in the proper location.
In such cases, the static pressure thrust of the system will cause the expansion joint to extend to the limit set by the control rods which will then preclude the possibility of further motion that would over-elongate the joint. Despite the limiting action that control rods have on the joint, they must be used when proper anchoring cannot be provided. It cannot be emphasized too strongly that rubber expansion joints, by virtue of their function, are not designed to take end thrusts and, in all cases where such are likely to occur, proper anchoring is essential. If this fact is ignored, premature failure of the expansion joint is a foregone conclusion.
Compression
Pipe sleeves or inside nuts can be installed on the control rods. The purpose of the sleeve is to prevent excessive compression in the expansion joint. The length of this pipe sleeve should be such that the expansion joint cannot be compressed beyond the maximum allowable compression.
Specifications
The exact number of control rods should be selected on the basis of the actual design/test pressure of the system. Always specify the mating flange thickness when ordering control unit assemblies.
Control Unit Assemblies
When an elastomeric expansion joint with a control unit assembly is to be installed directly to a pump flange, special care must be taken. Make sure that there is sufficient clearance behind the pump flange not only for the plates, but also for the nuts, bolts and washers. In cases where there is not sufficient clearance, the control rod plates on the pump end can be mounted behind the expansion joint flange if the expansion joint flange has a metal flange. If the elastomer expansion joint has an integral flange with split retaining rings, this method is not usually recommended as the split retaining rings may not have enough strength to withstand the total force encountered.
Retaining rings must be used to distribute the bolting load and assure a pressure tight seal. They are coated for corrosion resistance and drilled as specified.
The rings are installed directly against the back of the flanges of the joint and bolted through to the mating flange of the pipe. Steel washers are recommended under the bolt heads against the retaining rings; at a minimum at the splits. Rings are normally 3/8” (9mm) thick, but can vary due to conditions. The ring I.D. edge installed next to the rubber flange should be broken or beveled to prevent cutting of the rubber.
WARNING:
Expansion joints may operate in pipelines or equipment carrying units and/or gasses at elevated temperatures and pressures and may transport hazardous materials. Precautions should be taken to protect personnel in the event of leakage or splash.
Non-metallic joints should not be installed in inaccessible areas where inspection is impossible. Make sure proper drainage is available in the event of leakage when operating personnel are not available.
When assembling flange connections, it is recommended that a full complement of clean, new and high-strength A193-B7 bolting is consistently utilized. When Stainless Steel bolting is used, it should consist of the following:
When other bolting materials are employed, user should ensure new bolting material strength properties exceed the calculated bolt stress values generated in establishing the piping connection.
The following practices are strongly recommended:
NOTE: When bolting dissimilar materials, always tighten to the lowest recommended torque of the components in the joint. Employing higher torques may cause excessive deformation of the “softer” material contained in the joint. Position a ½” thick spacer between UIP International, Inc. PTFE-lined pipe or fittings and other plastic-lined components, particularly valves, should differences in the diameters of the raised plastic faces occur. *Belleville washers are not recommended for use with PTFE-lined products.
Retorquing
A retorque should be applied a minimum of 24 hours after the initial torque or after the first thermal cycle. Retorquing enables seating of the plastic and allows for the relaxation of the bolts. In the event that the system is intended to perform at elevated temperatures, hot water should be circulated at the maximum operating temperature of the process (if possible) for at least 24 hours. This process will allow the pipe system to experience one full thermal cycle.
After cool-down, retorquing of the system should be completed. Torqueing need only be completed on the system in the ambient, cooled state and never while the process is at an elevated temperature. This could cause excessive force to be exerted to the plastic faces. Never attempt to disassemble a flange joint in a hot system. Wait until the system has cooled to ambient temperature.
Hydrotesting
Typically after initial torque and retorque, a hydrotest should be carried out utilizing ANSI requirements. Experience has demonstrated that if the aforementioned procedure is adhered to, very few, if any flange joints will fail the hydrotest. If a flange joint leaks, first re-check the torque values and tighten in 10% increments over the specified bolt torques until completely sealed. If, however, 150% of the specified torque value has been reached and the flange joint continues to leak, stop the process and disassemble the flange joint. It is likely that something else is wrong, i.e, a scratched plastic face. The hydrotest must be successfully completed, and any existing leaks corrected before the pipeline can be approved and commissioned.
Regular Inspection
Regular inspection for leaks and periodic bolt tightening in accordance with good maintenance practice is recommended. Never attempt this process at an elevated temperature as damaging excessive force may be applied to the plastic faces.
Below are suggested Torque Values. The amount of torque required is different for all applications. They can change depending on media, temperature, pressure, material type, mating flange type and surface, specialty joints, if lubricant is used, installation offsets and environmental conditions.
Size = ft./lbs of torque
1″ to 2-1/2″ = 25 lbs. to 75 lbs.
3″ to 6″ = 40 lbs. to 85 lbs.
8″ to 12″ = 45 lbs. to 95 lbs.
14″ to 18″ = 50 lbs. to 110 lbs.
20″ to 28″ = 60 lbs. to 150 lbs.
30″ to 40″ = 75 lbs. to 200 lbs.
42″ to 48″ = 90 lbs. to 250 lbs.
Above 48″ to 144″ can vary greatly from 100 lbs to 500 lbs. depending on the application. See disclaimer above.
Single | Double Metal Bellows Expansion Joints are designed to absorb a specified amount of movement by the flexing of the thin-gauge convolutions. If proper care is not taken during installation, it may reduce the cycle life and the pressure capacity of the expansion joints, which could result in a premature failure of the bellows element or damage to the piping system. The following recommendations are included to avoid the most common errors that occur during installation When in doubt about an installation procedure, contact the manufacturer for clarification before attempting to install the Expansion Joints.
There are a couple of fundamental considerations when deciding the type of expansion joint to be used:
Is it a new plant?
If this is the case, it is more easily possible to create an optimal solution with respect to economic and technological concerns.
Does the plant already exist?
If this is the case, your expansion joint may need to be designed to operate in less than optimal conditions.
Questions for consideration:
Is the location of installation easily accessible? Do you require scaffolding or other complex equipment to install the expansion joint? Is a crane or other heavy equipment necessary to lift the expansion joint into place?
It is imperative that these and other similar conditions be considered prior to selecting the expansion joint design. It is at this stage that determination should be made on whether the expansion joint should be supplied open, closed on site, or supplied as a pre-assembled unit.
Movements:
The following movements, alone or in combinations, are compensated for by fabric expansion joints: Axial compression, axial elongation, lateral offset, angular offset and torsion.
The size and frequency of movements will affect the choice of expansion joint type. For large movements, convoluted and wave-form designs (moulded corners) or multi-layer expansion joints with scissor control guides should be used. They ensure that movements are controlled and help prevent damage to the fabric or heat pockets from occurring.
Mechanical Loads:
Fabric expansion joints can also compensate for vibrations and noise.
Consider the following when selecting an expansion joint: over stretching, abrasion by solid matter, hardened deposits and friction along the sleeve/baffle
Pressure:
Pressure affects the design (type of fabric and number of layers) of an expansion joint in the same way that temperature and medium do.
The following distinctions are made:
Flow Rate:
To allow for greater flow efficiency, fitting a sleeve/baffle may be recommended. When flow rates exceed 10 m/sec., a sleeve/baffle construction can protect the expansion joint from flutter or pulsation. Elastomer expansion joints, however, do not require a sleeve/baffle even at flow rates of up to 40 m/sec.
Medium:
The flow, or medium, is a major factor in the design of an expansion joint.
Temperature:
Varying temperatures play an important role in the design and construction of the expansion joint. The external covering materials are protected from thermal damage by the utilization of insulating layers; the thickness and number of layers depends upon the temperature.
The most important temperature values to consider are:
Ambient temperature
Expansion joint designs are typically dependent upon a given ambient temperature. Higher ambient temperatures can be tolerated by adjusting the thickness of the insulation accordingly.
Weathering
Cover plates have been shown to provide an effective measure of protection against rain, snow, sand storms, and other forces of nature. They also protect the joint from falling objects and build-up of debris along the top of the joint.
Temperatures below dew point
When temperatures are below dew point, the resulting increase in humidity also increases the chemical load on the expansion joint, and the duct work. Temperatures may drop below dew point as a result of the process being utilized, the shut-down of the plant, or if the plant is at partial operating capacity.
When temperatures are below dew point, they will affect:
Proper use of insulation inside the expansion joint, and around the joint frame’s external surfaces can be very effective in controlling the negative consequences of consistently cycling through dew point.
Installation Do’s
| Installation Don’ts
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The manufacturer’s warranty may be void if improper installation procedures have been used. | |