Seismic Loops – Unisource V-Loops Accommodate Pipe Motion in All Directions

Absorbing Pipe Movements During Seismic Activity with Seismic Loops

Unisource Seismic Loops. Specified by consulting engineers and building owners and installed by contractors throughout the world for many years, Unisource V-Loops solve the problems of pipe motion caused by thermal pipe growth and the unpredictable movements associated with seismic activity. Unisource seismic loops can perform the functions of large pipe loops or expansion joints, and in addition, can provide protection and flexibility in multiple planes during potentially catastrophic earthquakes.

Unlike large pipe loops, Unisource V-Loops take up a minimum of space, providing pipe motion accommodation solutions in limited space situations such as indoor piping. The small configuration of the Unisource seismic loops are also far less susceptible to the heat loss that must be dealt with in the case of large pipe loops.

Whereas metal bellows or rubber expansion joints will impose substantial anchor loads due to the effects of static pressure thrust, Unisource V-Loops will not introduce any thrust loads on the piping system. The unique construction of the braided V-shaped seismic loops creates a flexible product that does not expand when pressurized. A welded-on braid acts as a restraining device, even at extended pressures, yet allows tremendous flexibility. Anchor loads in regard to the Unisource V-Loops are confined to the relatively small spring forces required to deflect the flexible legs within the loop. Unlike expansion joints, a minimum of pipe guiding is required.

Unisource V-Loops are extremely easy to design in nested configurations. Due to the inherent V-design, standard Unisource V-Loops can simply be nested within each other with relatively tight centering. A substantial amount of space can be saved, and since no additional pipe extensions need to be installed in the Unisource V-Loops,

standard models can be used, saving cost and reducing delivery time.

The standard position for the Unisource V-Loop is in a horizontal pipe run, with the elbow pointing straight down. Positioning is versatile, however, and the loops can be installed in many other positions such as laying the loop horizontal, positioning the elbow straight up, or positioning for vertical pipe run. In installations other than the standard position, Unisource can provide a support eyelet to allow a cable or rod to support the weight of the loop and its contents.

Unisource V-Loops can be used for a variety of fluids and gases. Loops can be constructed using stainless steel hose and braid with carbon steel end fittings and elbows, or with bronze hose and braid with copper end fittings and elbows. End fitting options include flanges, male threads, beveled weld ends, grooved ends, and copper sweat. Use Unisource V-Loops for applications such as heating and cooling water in HVAC systems; moderate velocity steam; natural gas; medical gases; fire sprinkler piping; and selected process applications. Drain ports can be added where required.

For higher pressure applications, Unisource V-Loops can be constructed using double braided hose legs. Consult Unisource for specific pressure ratings.

Standard Unisource V-Loops are offered for either 2” or 4” of motion from center-line in axial and offset planes. Loops for even greater motions can be constructed upon request.

All Unisource V-Loops are shipped complete with installation instructions wire tagged to each product. Unisource offers loops for applications under the auspices of the CSA/AGA, NFPA, and U.L.

Unisource also manufactures a comprehensive line of rubber and metallic expansion joint. Check out our Expansion Joints web section for more information.

V-Loops
VLoop-Brochure-Link

V-Loop Basic Information

Absorbing Thermal Pipe Movements

Unisource V-Loops are an ideal option for compensating for thermal pipe growth. Often, thermal pipe growth must be absorbed in piping systems where the substantial anchoring systems that bellows expansion joints would require are not present. Since these “V” shaped flexible hose loops do not impose pressure thrust forces on the anchoring system, anchor loads are very low. The only forces involved are the spring forces required to flex the loops. Unisource V-Loops are an in-line connector and consist of a 90-degree pipe elbow with a flexible stainless steel or bronze hose leg connecting to each end of the elbow. 45-degee pipe elbows are located at the ends of the flex leg and end fittings are welded to the 45-degree elbows. End options are flanges, pipe threads, beveled weld ends, grooved ends, and copper sweat ends. Standard Unisource V-Loops are rated for either 2” or 4” of motion, but can be build to absorb greater movements. Since Unisource V-Loops do not impose thrust forces on the pipe system, a minimum of guiding is required. For steam applications, a drain port can be added at the center elbow. Loops can be configured with the 90-degree elbow hanging straight down or with support at the 90-degee elbow, can be positioned in an inverted position, horizontal, or in a vertical riser application.

See the HVAC section under Special Market Focus more more information and submittal on Unisource V-Loops.

Diagram of Unisource V-Loop with descriptions

V-Loop Basic Information

Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Drain Port
End Connections
Carbon steel, stainless steel, or copper 160 PSIG to 1335 PSIG (Depending on size). Double braided higher pressure loops also available 1/2″ through 12″ Choose either 300 series stainless steel or bronze 2” or 4″ are standard. More motion can be accommodated upon request Carbon steel or bronze with tapered plug Flanged, threaded, beveled weld end, grooved, copper sweat

Series 420 V-Loops – Flanged

 

A flanged end loop with carbon steel Class 150 plate flanges as standard ends. Raised face flanges (Series 421) or virtually any other flange configuration can also be ordered. Schedule 40 carbon steel elbows are also standard, but can be specified in other materials.

As in other configurations of Unisource seismic loops, choose from either 2” or 4” of motion from center-line. For steam service, Unisource recommends placing the loops in either an inverted or horizontal installation when conveying steam. A drain port should also be specified for steam service. Unisource can also add an eyelet at the 90 degree elbow to accommodate a support rod or cable. Pre-designed in sizes from 1-1/2 inch through 12 inch. Available in custom construction up to 18 inch diameter and in movements as great as 24 inch.

Unisource Series 420 flanged V-Loop
420FlyerPagePic

Series 420 Flanged V-Loop – Product Brochure

420-2SubmPagePic

Series 420-2 V-Loop – Submittal

420-4_SubPagePic

Series 420-4 V-Loop – Submittal

Hose
End Fittings
Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Type 321 stainless steel annular corrugated hose Painted carbon steel 150# drilled plate flanges. 300# drilled flanges or stainless steel flanges available upon request Painted Sch. 40 carbon steel 90-degree and 45-degree elbows. Stainless steel available upon request 160 to 472 PSIG 1-1/2″ through 12″ Type 304 stainless steel. Sizes 8″ and larger are braided braid 2″ or 4″ Standard

Series 425 Threaded &

Series 430 Weld End V-Loops

 

Series 425 is a loop with carbon steel male NPT threaded ends as standard. Female union ends can also be specified (Series 426). As in other configurations of Unisource V-Loops choose from either 2” or 4” of motion from center-line. For steam service, Unisource recommends placing the loops in either an inverted or horizontal installation when conveying steam. A drain port should also be specified for steam service. Unisource can also add an eyelet at the 90-degree elbow to accommodate a support rod or cable.

Series 430 loops are configured with carbon steel schedule 40 beveled weld ends as standard. As in other configurations of Unisource V-Loops choose from either 2” or 4” of motion from center-line. For steam service, Unisource recommends placing the loops in either an inverted or horizontal installation when conveying steam. A drain port should also be specified for steam service. Unisource can also add an eyelet at the 90 degree elbow to accommodate a support rod or cable.

Shows Unisource Series 425 threaded V-Loop
425FlyerPagePic

Series 425 Threaded V-Loop – Product Brochure

425-2SubmPagePIc

Series 425-2 Threaded V-Loop – Submittal

425-4SubmPagePic

Series 425-4 Threaded V-Loop – Submittal

430FlyerPagePic

Series 430 Weld End V-Loop – Product Brochure

430-2SubmPagePic

Series 430-2 Weld End V-Loop – Submittal

430-4SubmPagePic

Series 430-4 Weld End V-Loop – Submittal

Hose
End Fittings
Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Type 321 stainless steel annular corrugated hose Painted carbon steel 150# drilled plate flanges. 300# drilled flanges or stainless steel flanges available upon request Painted Sch. 40 carbon steel 90-degree and 45-degree elbows. Stainless steel available upon request 160 to 1075 PSI 1-1/2″ through 12″ Type 304 stainless steel. Sizes 8″ and larger are braided braid 2″ or 4″ Standard

Series 435 V-Loops – Grooved Ends

 

Series 435 Unisource V-Loops loops are constructed with carbon steel standard grooved ends for easy installation.

As in other configurations of Unisource V-Loops, choose from either 2” or 4” of motion from center-line. Unisource can also add an eyelet at the 90-degree elbow to accommodate a support rod or cable.

Unisource Series 435 Grooved End V-Loop
Series435FlyerPagePic

Series 435 Grooved End V-Loop – Brochure

435-2SubmPagePic

Series 435-2 Grooved End V-Loop – Submittal

435-4SubmPagePIc

Series 435-4 Grooved End V-Loop – Submittal

Hose
End Fittings
Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Type 321 stainless steel annular corrugated hose Painted carbon steel grooved ends Painted Sch. 40 carbon steel 90-degree and 45-degree elbows. Stainless steel available upon request 160 to 472 PSIG 1-1/2″ through 12″ Type 304 stainless steel. Sizes 8″ and larger are braided braid 2″ or 4″ Standard

Series 440 V-Loops – Copper Sweat

Series 440 Unisource loops are designed specifically for copper piping systems. They are constructed with copper female sweat ends and copper elbows and either stainless steel braided hose or bronze braided hose, depending on size.

As in other configurations of Unisource V-Loops, choose from either 2” or 4” of motion from center-line. Unisource can also add an eyelet at the 90-degree elbow to accommodate a support rod or cable.

Bronze braided V-Loop with copper ends
440SweatFlyerPagePic

Series 440 Copper Sweat V-Loop – Brochure

440-2SmallSubPagePic

Series 440-2 Sweat End – 1/2″ Thru 2″

V-Loop – Submittal

440-2LargeSubPagePic

Series 440-2 Sweat End – 2-1/2″ Thru 4″

V-Loop – Submittal

440-4SmallSubPagePic

Series 440-4 Sweat End – 1/2″ Thru 2″

V-Loop Submittal

440-4LargeSubPagePic

Series 440-4 Sweat End – 2-1/2″ Thru 4″

V-Loop Submittal

Hose
End Fittings
Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Annular bronze corrugated hose. (Sizes 2-1/2″ and larger are stainless steel corrugated annular hose) Copper female sweat Copper 90-degree and 45-degree elbows. (Sizes 2-1/2″ and larger uses 304 stainless steel 90 degree center elbow). Copper to stainless welds utilize silver braze method) 270 PSIG to 642 PSIG (Depending on size) 1/2″ through 4″ Single bronze braid. (Sizes 2-1/2″ and larger are single braid annular T304 stainless steel) Choose either 2” or 4″ as standard product. Greater movement capabilities can be accommodated upon request

Series 445 & Series 450 Seismic Loops – CSA Rated For Natural Gas – Threaded & Weld End

 

Unisource Series 445 threaded and Series 450 weld-end V-Loops are designed specifically for natural gas piping and are certified by CSA International for gas piping applications (Certification Report No. 190623-1131571).

Series 445 and Series 450 gas loops are constructed with stainless steel hose and braid, carbon steel Sch 40 elbows and either male NPT ends (Series 445) or beveled weld ends (Series 450). Unisource gas loops are rated for minimum working pressures of 150 PSIG, with extremely high burst to working pressure ratios. Drain port and hanger eyelets are options.

Series 445 and Series 450 V-Loops are rated for 4” of motion from center-line. Size range is from 1/2” through 4”.

CSA Rated V-Loops
445-450CSAFlyerPagePic

Series 445 & 450 CSA V-Loops – Brochure

445-4CSASubPagePic

Series 445 CSA Threaded V-Loop – Submittal

450-4CSASubPagePic

Series 450 CSA Weld End V-Loop – Submittal

Hose
End Fittings
Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Corrugated stainless steel Carbon steel Male NPT or beveled weld ends Carbon steel Sch 40 150 PSIG 1/2″ through 4″ Single braid of stainless steel 4” allowable as standard product. Greater movement capabilities can be accommodated upon request

Series 455 – “MedFlex” Medical Gas Seismic Loops

Series 455 “MedFlex” loops are produced specifically for medical gas applications and are documented, purged, and brazed to NFPA (National Fire Protection Association) standards. In addition, “MedFlex” loops are cleaned, capped, and bagged in accordance with CGA (Compressed Gas Association) G-4.1

“MedFlex” loops are constructed with bronze hose and braid, copper return elbow, and copper sweat end connections. Sizes 2-1/2” through 4” utilize stainless steel hose and braid, stainless steel return elbow, and copper sweat end fittings silver brazed to the assembly.

Unisource V-Loops can be included into specific seismic bracing designs for submission to the California Office of Statewide Health Planning and Development (OSHPD) for use in health care facilities.

Unisource Series 455 Seismic Loop for Med Gas
455MedFlyerPagePIc

Series 455 “MedFlex” V-Loops – Brochure

455SmallSubPagePic

Series 455 “MedFlex” 1/2″ to 2″ V-Loop – Submittal

455LargeSubPagePIc

Series 455 “MedFlex” 2-1/2″ to 4″ V-Loop – Submittal

Hose
End Fittings
Elbows
Pressure Range
Sizes
Braid
Allowable Motions
Bronze corrugated hose (stainless steel in sizes 2-1/2” thru 4”) Copper sweat Copper return elbow (stainless steel return elbow on sizes 2-1/2” thru 4”.) (Copper to stainless welds utilize silver braze method) 566 to 232 PSIG (depending on size) 1/2″ through 4″ Bronze (stainless steel in sizes 2-1/2” thru 4”) 4″

Unisource “FireV” U.L. Rated V-Loops

for Fire Sprinkler Systems

 

Unisource “FireV” flexible seismic loops are built to accommodate the unpredictable movements of fire sprinkler piping during seismic incidents. The innovative designs of our “FireV” combines flexible, braided stainless steel hose and braid with piping elbows to provide an engineered solution to seismic movement, while not requiring a change of direction. Tested and listed by U.L. (Underwriters Laboratories) for fire sprinkler applications, Unisource FireV loops can absorb as much as 24″ of seismic motion in all three planes of movement.

Also, unlike any other fire sprinkler loops on the market, the V-configuration allows for fire sprinkler piping to be nested within other adjacent V-Loops. This feature saves space and eliminates the need for successively longer pipe extensions at the base of the loop.

Basic “FireV” construction includes Schedule 40 carbon steel 90-degree center elbow and 45-degree elbows at either end (eliminating the need for a change of piping direction).

End fittings can be carbon steel grooved ends, carbon steel male NPT, carbon steel beveled weld end, and carbon steel flanges.

Our standard listed seismic movement limits are generally 4-inches, 8-inches, or 24-inches, but any rating within 24-inches may be specially ordered. Each “FireV” loop is labeled with the appropriate U.L. identification, listing number, and part number. “FireV” loops are 100% pre-tested to U.L. standards prior to shipment and are shipped with installation instructions wire-tagged to the loop. Special shipping containers are used at no additional cost to protect the loops during shipment and during job-site storage. Sizes range from 1/2-inch through 8-inch diameter.

End configurations include Style 436 grooved, Style 421 flanged, Style 426 threaded, and Style  431 with beveled weld ends.

Unisource “FireV” U.L. rated fire sprinkler loops are also listed for use in Canada.

Seismic Fire Loop
Flexible loops for Fire

“FireV” Seismic V-Loop – Booklet

pressure drop for FireV loops

Pressure Drop Information

436-4SubPagePic

Series 436-4 Grooved Submittal

436-8SubPagePic

Series 436-8 Grooved Submittal

421-4SubPagePic

Series 421-4 Flanged Submittal

421-8SubPagePic

Series 421-8 Flanged Submittal

426-4SubPagePic

Series 426-4 Threaded Submittal

426-8SubPagePic

Series 426-8 Threaded Submittal

431-4SubPagePic

Series 431-4 Weld End Submittal

431-8SubPagePic

Series 431-8 Weld End Submittal

Hose
Elbows
Braid
Drain Port
Type 321 stainless steel annular corrugated hose Painted Sch. 40 carbon steel 90-degree and 45-degree elbows. Stainless steel available upon request 300 Series stainless steel Carbon steel with tapered plug

Unisource “FireU” U.L. Rated U-Shaped Seismic Loops for Fire Sprinkler Systems

A tried-and-true stainless steel braided flexible seismic loop for fire sprinkler systems.

Unisource “FireU” flexible U-shaped seismic loops are built to accommodate the unpredictable movements of fire sprinkler piping during seismic incidents. The innovative designs of our “FireU” combines flexible, braided stainless steel hose and braid with piping elbows to provide an engineered solution to seismic movement, while not requiring a change of direction. Tested and listed by U.L. (Underwriters Laboratories) for fire sprinkler applications, Unisource FireU loops can absorb as much as 24″ of seismic motion in all three planes of movement.

Basic “FireU” construction includes Schedule 40 carbon steel 180-degree center elbow and 90-degree elbows at either end (eliminating the need for a change of piping direction)

End fittings can be carbon steel grooved ends, carbon steel male NPT, carbon steel beveled weld end, and carbon steel flanges. Our standard listed seismic movement limits are generally 4-inches, 8-inches, or 24-inches, but any rating within 24-inches may be specially ordered. Each “FireU” loop is labeled with the appropriate U.L. identification, listing number, and part number.

“FireU” seismic loops are 100% pre-tested to U.L. standards prior to shipment and are shipped with installation instructions wire-tagged to the loop. Special shipping containers are used at no additional cost to protect the loops during shipment and during job-site storage. Sizes range from 1-1/2-inch through 8-inch diameter.

End configurations include Style 436U grooved, Style 421U flanged, Style 426U threaded, and Style 431U with beveled weld ends.

fire loop
436U-4SubPagePic

Series 436U-4 Grooved Submittal

436U-8SubPagePic

Series 436U-8 Grooved Submittal

Hose
Reinforcement
End Fittings
Elbows
Branding
Sizes
Allowable Motions
Drain Port
Type 321 stainless steel annular corrugated hose Stainless steel braid Carbon steel grooved. Also available in flanged, threaded & weld end styles. Painted Sch. 40 carbon steel 180-degree and 90-degree elbows. Stainless steel available upon request.   U.L. Labeled for Fire Sprinkler Systems  1-1/2″ through 8″  4″ or 8″ of movement are standard. Special order up to 24″ of movement.  Carbon steel with tapered plug

Want to speak to a professional?

THANK YOU FOR TAKING THE TIME TO VISIT OUR SITE. OUR CUSTOMER SERVICE TEAM IS AVAILABLE TO ASSIST YOU MONDAY THROUGH FRIDAY, 8 A.M. TO 5 P.M. FOR ADDITIONAL INFORMATION PERTAINING TO THE SERVICES OR PRODUCTS THAT WE PROVIDE OR IF YOU NEED AN ESTIMATE, CONTACT ONE OF OUR OFFICES.

Slider