Nibco 4551-A Socket Flange S -...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$20.06
Nibco 4551-A Socket Flange S - PVC Schedule 80, Two-Piece Van Stone

Nibco 4551-A Socket Flange S - PVC Schedule 80, Two-Piece Van Stone

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Model: CA25450

In Stock (leaves warehouse same day if ordered before 3pm ET)

$20.06
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The dark grey PVC socket flange features a female socket connection. The Van Stone flange assembly includes a connector hub, PVC coated aluminum flange ring and a PVC flange ring. Chemtrol® fittings connect PVC piping lengths together with solvent cementing, threading or flanging to create a highly reliable, leak-free system. Please refer to Chemtrol technical data sheets, chemical resistance guides and catalogs for engineering and installation information. PVC Schedule 80 has the highest long-term hydrostatic strength of any other major thermoplastic material used for piping. Chemtrol® PVC fittings are lightweight, easy to install, maintenance-free, and will not rust, scale, pit or corrode. Chemtrol® premium line of plastic fittings is backed by a 1-year limited warranty. Because Chemtrol® is a NIBCO brand the flow-control fittings are unsurpassed in quality, performance and longevity.

  • Maximum service temperature 140-DegreeF
  • Universal Part No. 854
  • Van Stone two-piece design with webbed ring and separate rotating hub
  • Female socket connections and flange connections compatible with ANSI B16.5 Class 150
  • Do not use or test with compressed air or other gases
  • ASTM F1970
  • NSF/ANSI Standard 14
  • NSF/ANSI/CAN-61

Manufacturer Resources

Product Specs

All Application(s):
Lead-Free
All Basic Material:
PVC - Polyvinyl Chloride
Classification:
PVC Sch 80 Flanges
End Connection:
Socket Weld
Pipe Schedule:
80
Plastic End Connection Type:
S Socket
Product Group:
Fitting
Product Type:
PVC Sch 80 Flanges
System Use:
Commercial Plumbing, Industrial, Irrigation, Lead Free*
Product Subgroup:
Flange
Department:
Plumbing
Product Color:
Dark Grey
Country Of Origin:
United States

Nibco CA25450 – Frequently Asked Questions

1) Will a Nibco Chemtrol 4551-A Van Stone flange bolt up to my existing Class 150 metal flange?
Yes. The 4551-A PVC flange is built with flange connections compatible with ANSI B16.5 Class 150 bolt patterns, so it mates to a Class 150 companion flange, valve, or pump connection of the same nominal size. Because it is a Van Stone two-piece design, the ring rotates independently of the hub, which is what lets you line the bolt holes up after the hub is already cemented to the pipe. That rotating ring is the main reason fitters reach for a Van Stone over a one-piece flange on a run that is already fixed in place.
2) Does the Nibco 4551-A flange glue onto the pipe or thread on?
It solvent cements. The 4551-A hub has a female S socket end connection, so the pipe slides into the socket and is joined with PVC primer and solvent cement. There are no threads on the pipe side. If your run is threaded and you do not want to cut and cement, you need a threaded (FPT) Schedule 80 flange instead, not this one.
3) What is the maximum temperature a PVC Schedule 80 Van Stone flange can handle?
140 degrees F is the maximum service temperature for the 4551-A. PVC loses pressure capability as temperature climbs, so hot water, boiler returns, steam, and hot condensate lines are out. For a process line that runs above 140F you need CPVC or metal, not this flange.
4) Can I use this PVC flange on compressed air?
No. The Chemtrol 4551-A is for liquid service only, and the manufacturer states directly that it must not be used or tested with compressed air or other gases. That includes pressure testing: hydrostatic test only, never an air test. A PVC failure under stored gas energy is a shrapnel event, which is why the rule is absolute rather than a recommendation.
5) Is the Nibco 4551-A PVC flange approved for potable water?
It is certified to NSF/ANSI Standard 14 and NSF/ANSI/CAN 61, and it is listed as a lead-free application, which is the pairing a plumbing inspector looks for on potable water. It also carries ASTM F1970. Those listings are what let it go into a commercial potable system rather than being limited to drain or process duty.
6) What comes in the box with a Van Stone flange, and what else do I need to buy to make the joint?
The 4551-A assembly ships as the connector hub, a PVC coated aluminum flange ring, and a PVC flange ring. Bolts, nuts, and the gasket are not part of the assembly, so order those separately along with PVC primer and solvent cement for the socket joint. Budget the fastener count off the Class 150 bolt pattern for your size.
7) What pipe sizes does the Nibco Chemtrol 4551-A PVC Schedule 80 flange come in?
Thirteen sizes, from 1/2 inch up to 12 inch: 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 4, 6, 8, 10 and 12 inch. Size to the pipe, not the bolt circle. The socket is sized for Schedule 80 PVC pipe of that nominal size, and the flange face follows the Class 150 pattern for the same size.
8) Why pick a Van Stone flange instead of a standard one-piece PVC flange?
Alignment. A one-piece flange has the bolt holes cast into the same body as the socket, so once you cement it to the pipe the holes are wherever they landed and you have to rotate the pipe. The 4551-A separates the two: the hub cements to the pipe and the webbed ring spins freely around it, so you cement first and index the bolt holes afterward. That matters most on a tie-in to a pump or a valve you cannot move, or on a large diameter line where rotating the pipe is not an option.
9) Will a Schedule 80 PVC flange work on Schedule 40 PVC pipe?
Yes on the pipe fit. Schedule 40 and Schedule 80 PVC share the same outside diameter at a given nominal size, so the 4551-A socket accepts Schedule 40 pipe of the matching size. What changes is the rating of the system: Schedule 40 pipe has a thinner wall and a lower pressure rating, so the run is only as strong as the pipe, not the Schedule 80 flange. Keep the 140F service ceiling in mind either way.
10) How do I order the right Nibco 4551-A flange, and what part number do I give my supplier?
Pipe size is the only thing you specify. Each size carries its own Chemtrol part number: 1/2 inch is CA25446, 3/4 inch CA25448, 1 inch CA25450, 1-1/4 inch CA25452, 1-1/2 inch CA25454, 2 inch CA26650, 2-1/2 inch CA25458, 3 inch CA25460, 4 inch CA25470, 6 inch CA25480, 8 inch CA25490, 10 inch CA25500, and 12 inch CA25550. Note the 2 inch breaks the numbering pattern, so quote CA26650 rather than assuming the next number in the sequence.
11) Is a PVC Van Stone flange strong enough for an industrial line, or should I be using metal?
PVC Schedule 80 has the highest long-term hydrostatic strength of the major thermoplastics used for piping, and the 4551-A is rated to the Class 150 flange standard, so it holds its own on cold liquid service in industrial and irrigation work. The limits are heat and gas, not strength: 140F ceiling, liquids only. Where the run stays cold and wet, PVC also buys you corrosion immunity that metal does not have. It will not rust, scale, pit, or corrode, which is why it shows up on water treatment and chemical feed lines that eat steel flanges.
12) Can I bolt this PVC flange directly to a pump or valve without a gasket?
No. A flanged PVC joint needs a full face gasket between the mating faces, and it is not included with the 4551-A assembly. Tighten in a star pattern to the flange manufacturer's torque, not to the limit of your wrench: overtightening is the single most common way a PVC flange cracks, because the PVC ring will not tolerate the bolt load a steel flange shrugs off.
13) Is the dark grey PVC flange the right one for an irrigation main or a chemical process line?
The 4551-A is listed for commercial plumbing, industrial, and irrigation service, and the dark grey color is standard Chemtrol PVC (grey is PVC, not CPVC, so do not read the color as a temperature upgrade). For chemical duty, PVC handles a wide range but not everything: check the fluid against the Chemtrol chemical resistance guide before committing, because compatibility is per-chemical and per-concentration.
How fast can I get the Nibco CA25450 delivered?
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Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Nibco CA25450 come with a warranty?
Absolutely. The Nibco CA25450 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Nibco CA25450?
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