Attribute Schema Library
Attribute schemaplumbing & PVF

Backflow Preventer Attributes

A backflow preventer stops non-potable water reversing into the potable supply. It runs 1/4 in dual checks to 12 in fire-service detector assemblies, split by degree of protection: RP for high hazard, DC for non-health hazard, plus vacuum breakers and the fire-line detector versions. Buyers: plumbing, mechanical, fire sprinkler and irrigation contractors, purveyors, the engineers writing the submittal.

Nomenclature collides: RP, RPZ, RPZA and RPBA name the same device, and Ferguson's type facet lists "Reduced Pressure Zone Assembly" and "Reduced Pressure Principle Assembly" as separate values. Variants explode: base model x size x shutoff trim (QT ball, NRS, OS&Y, butterfly, none) x strainer x test-cock orientation turns one 909 into dozens of MPNs, carried in a suffix string, not a field.

Authority splits three ways: ASSE lists the product standard, USC's Foundation approves by model and size on a three-year renewal, the purveyor decides what it accepts. None of it is in the price file, and head loss, lay length with shutoffs and relief port area sit in chart images inside PDFs.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Assembly Type
enum
Reduced Pressure Principle Assembly (RP)

The first filter every buyer touches. Decides hazard suitability, test procedure, whether a relief drain is needed, and which ASSE standard applies.

Nominal Size
enum · in (DN)
3/4 in (DN 20)

Drives price, weight, lay length and which USC approval line applies. Approvals and dimensions are granted per size, not per model.

End Connection
enum
FNPT (ANSI/ASME B1.20.1)

Threaded, flanged, grooved, union and sweat are not interchangeable. Determines what the installer needs on the pipe before the valve lands.

Body Material
enum
Low-lead cast bronze (ASTM B584)

Bronze below 2 in, epoxy-coated ductile iron or stainless above. Sets weight, corrosion service, and whether the casting is potable-legal.

Maximum Working Pressure
number · psi
175 psi (12.1 bar)

Standard rating across most potable assemblies is 175 psi. Anything above that is a deliberate spec and buyers filter for it.

Working Temperature Range
range · °F
32-140°F (0-60°C)

Varies by model and hides a continuous vs intermittent split. Wrong range on a boiler feed or reclaim line destroys the elastomers.

Manufacturer Part Number
identifier
0391010

The orderable code. Distinct from the series: one series spans dozens of MPNs by size and trim.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Hazard Level
enum
High hazard (health hazard)

High hazard requires an RP; a double check is only acceptable on non-health hazard. This is the code question that decides RP vs DC.

Shutoff Valve Type
enum
OS&Y gate valves

Ball, NRS gate, OS&Y gate, butterfly, PIV or supplied less shutoffs. Changes lay length, price, clearance and whether position is visible.

Service
enum
Potable water

Fire service assemblies need UL/FM marks and are lead-free exempt. A domestic model on a fire line fails inspection.

Overall Lay Length
number · in
17-3/4 in (2 in RP, incl. shutoffs)

Retrofit decides on face-to-face with the shutoffs on. Manufacturer tables usually publish the body dimension, which is the shorter number.

Test Cocks (Qty x Size)
text
4 x 1/4 in

Testers need them and inspectors count them. RP and DC assemblies carry four; PVBs carry two. Size grows with the assembly.

Series & Option Suffix
identifier
LF909-QT-S

Where the real configuration lives: QT ball valves, S strainer, FT flare test fitting, TCU test cocks up, NRS/OSY trim, FS flood sensor.

Weight
number · lb
29.2 lb (2 in, with shutoffs)

Decides freight class, rigging and whether one person sets it. A 2 in RP is ~30 lb; a 6 in flanged unit needs a lift.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

ASSE Standard Listing
enum
ASSE 1013

The product standard the assembly is listed to. 1013 RP, 1015 DC, 1020 PVB, 1056 SVB, 1047 RPDA, 1048 DCDA, 1024 dual check.

Third-Party Approvals
text
NSF/ANSI/CAN 61 & 372; IAPMO; CSA B64.4; AWWA C511

What the purveyor and the submittal reviewer actually read. NSF/ANSI/CAN 61 and 372 for potable, CSA and AWWA for conformance.

UL/FM Fire Service Approval
boolean
UL Classified (UL 1469); FM Approved

Fire protection assemblies must carry the fire mark. Domestic potable models do not bear it and are not code-compliant on a fire line.

Country of Origin
enum
United States

Required for customs, and for Buy America / AIS language on municipal and federal water work.

The fields that aren't in the schema at all

What most backflow preventers catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Supplier signal
+ USC FCCCHR Approval Status & Renewal Date

USC publishes its approved-assembly list by type, manufacturer, model and size, on a three-year renewal cycle. Distributor catalogs carry the ASSE listing and stop there: no USC field, no expiry.

Purveyors that require current USC listing reject the assembly at inspection. It gets installed, tested, then torn out at the contractor's cost, and yours.

Competitor signal
+ Overall Lay Length Including Shutoff Valves

Specialist backflow sites publish standalone lay-length reference tables because catalogs don't carry the field. Manufacturer tables footnote that the dimension shown is less shutoffs: body only.

Retrofit buyer measures the old assembly, orders on body length, and the new unit with its OS&Y valves won't fit the vault. Freight both ways on a 200 lb valve.

Search signal
+ Approved Installation Orientation

Assemblies are approved horizontal, vertical, N-pattern or Z-pattern, and not every model is approved in every position. Buyers searching "vertical RPZ" get the whole size range back, unfiltered.

Tight mechanical rooms and vaults are where orientation decides the sale. Without the field the buyer calls, and the RFQ goes to whoever answered it on the page.

Marketplace signal
+ Lead-Free Certification Basis (NSF/ANSI 372)

Manufacturers ship near-identical model pairs: 825Y and LF825Y, 909 and LF909. The standard-material datasheet warns it is illegal to install on plumbing for human consumption in the US.

A one-character model difference decides whether the part is legal on potable. A blanket "Lead Free: Yes" with no certification basis ships the wrong one.

Supplier signal
+ Relief Valve Discharge Port Area / Air Gap Fitting

RP datasheets publish relief port area (0.63 sq. in. for 3/4-1 in, 1.19 sq. in. for 1-1/4-2 in) and a matching air gap fitting model. Catalog records carry neither.

The floor drain and air gap get sized on site or not at all. A relief discharge event floods the mechanical room and the backflow preventer takes the blame.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way plumbing & PVF suppliers spell it. A filter only works once they agree.

Assembly Type
RPZRPRPZARPBAReduced Pressure ZoneRed. Press. Principle
Reduced Pressure Principle Assembly (RP)

Ferguson's own type facet lists "Reduced Pressure Zone Assembly" and "Reduced Pressure Principle Assembly" as separate values.

End Connection
FNPTNPTFemale NPTThreadedFIPIPS Thread
FNPT (ANSI/ASME B1.20.1)

Zurn writes "Threaded ANSI B1.20.1", Watts writes "NPT ANSI/ASME B1.20.1", Ferguson labels the same part "Bronze FNPT".

Nominal Size
3/4"3/4 in0.7520mmDN203/4 IN.
3/4 in (DN 20)

Metric arrives as 8/10/15/20 mm on the same datasheet that says 1/4, 3/8, 1/2, 3/4 in. Text sort puts 10 in ahead of 2 in.

Body Material
BronzeCast BronzeLF BronzeLow Lead Cast BronzeASTM B584Lead-Free Bronze
Bronze, low-lead cast (ASTM B584)

"Bronze" and "Low Lead Cast Bronze ASTM B 584" are the same casting, but only one of them tells the buyer it is potable-legal.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Is it on the USC list, and is the approval still current for this size?
  • Do I need an RP here, or will a double check pass?
  • Does it come with the shutoffs, or am I buying those separately?
  • Can I mount it vertical? I don't have the wall for a horizontal.
  • Is this the lead-free version? It's going on potable.
  • What's the face-to-face with the OS&Y valves on it? I'm replacing a 3 in.
  • Is it UL/FM for a fire line, or is this the domestic model?
  • What's the head loss at rated flow? Do I need a booster?

What channels require

The same SKU, different mandatory fields per destination.

Distributor faceted catalog (own site)
Assembly TypeNominal SizeEnd ConnectionBody MaterialHazard LevelASSE Standard Listing
Amazon Business
GTIN/UPCBrandManufacturer Part NumberCountry of OriginMaximum Working PressureWeight
Engineer submittals & BIM (MasterFormat 22 11 19)
Series & Option SuffixNominal SizeOverall Lay LengthWorking Temperature RangeASSE Standard ListingThird-Party Approvals

Backflow Preventers data, in practice

RPZ, RP, RPZA, RPBA — are these all the same thing?

Yes. All four name a reduced pressure principle assembly: two independently acting check valves plus a hydraulically dependent differential relief valve, listed to ASSE 1013. The variation is historical — manufacturers, purveyors and code officials each settled on a different abbreviation, and supplier feeds inherit whichever one the source document used. Ferguson's own type facet carries "Reduced Pressure Zone Assembly" and "Reduced Pressure Principle Assembly" as two separate values, which splits one filter into two and halves the count under each. Governed to a single value with the rest as synonyms, the facet reconciles and search recall improves without touching the SKUs.

If I already store the ASSE listing, do I still need a USC approval field?

Yes — they answer different questions. ASSE 1013 or 1015 says the design passed a product standard. USC's Foundation for Cross-Connection Control and Hydraulic Research runs a separate laboratory and field evaluation and approves the assembly by type, manufacturer, model and size, for three years, subject to renewal. An assembly can be ASSE listed and not on the current USC list. Many purveyors will only accept assemblies on that list at the time of installation, so the field needs a status and a renewal date, held per size, not a single flag on the parent model.

Why do temperature ranges differ between models that look identical?

Because the number depends on the elastomers and on whether the rating is continuous or intermittent, and because catalogs collapse both into one "max temp" cell. Febco's 825Y is specified 32°F to 140°F. Watts' 909 is rated to 110°F continuous with 140°F intermittent. Zurn's 975XL2 in 1/4 to 1/2 in carries a 180°F maximum. Storing a single scalar loses the continuous/intermittent distinction, which is the one that matters on boiler feed, reclaim and process water. Carry it as a range plus a duty qualifier, and let the model-level value come from the datasheet rather than a category default.

How should the lead-free and standard-material versions be modelled?

As separate records, not a flag on one. They are different castings with different model numbers — 825Y and LF825Y, 909 and LF909 — and different legal standing. The Safe Drinking Water Act limit of 0.25% weighted average lead applies to anything in a potable line; NSF/ANSI 372 is the certification that demonstrates it. Standard-material datasheets carry an explicit warning that the product is illegal in US plumbing supplying water for human consumption. Fire protection service is generally exempt, which is why both versions stay in the line card. Store the certification basis, not just "Lead Free: Yes".

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