How to Read a Basin Mixer Datasheet: Flow Rate at 3 Bar, Minimum Pressure, Cartridge Size and Inlet Connections

Most disputes between a faucet factory and an importer are not about quality. They are about a number that was read one way in the quotation and another way on site. A datasheet is a contract written in millimetres, litres per minute and bar — and like any contract, the meaning sits in the qualifiers, not the headline figures.

Here is how to read a basin mixer datasheet line by line, and what to challenge when a line is missing.

The header block

Before the numbers, four identifiers should be present: model reference, product type (single-lever basin mixer, deck-mounted, one-hole), nominal size, and finish. A serious datasheet also states the body material and, for brass, the grade — CW617N is the common European free-cutting brass, while CW602N is the dezincification-resistant grade used where aggressive water is a risk.

If the finish is described only as "chrome", ask for the coating standard. EN 248 defines electrodeposited nickel-chrome coatings for sanitary tapware and the associated test regime. "Chrome" on its own tells a specifier nothing.

Line 1: Flow rate at 3 bar

This is the most quoted and least understood figure. Three qualifiers matter.

**3 bar is a reference pressure, not the site pressure.** Flow through a tap rises with the square root of dynamic pressure. A mixer rated 12 l/min at 3 bar gives roughly 8.5 l/min at 1.5 bar and 7 l/min at 1 bar. To estimate at another pressure: Q₂ = Q₁ × √(P₂ ÷ P₁). If a datasheet quotes a flow rate without stating the pressure, the number is unusable.

**It should be a dynamic reading.** Static pressure measured at a closed tap includes no losses; the flow figure must come from a test with water running and the outlet fitted as supplied — aerator or restrictor included. This is the basis on which EN 817 and EN 246 requirements are assessed.

**It is not a maximum.** A basin mixer rated 5.5 l/min at 3 bar with a restrictor fitted may pass 14 l/min with the insert removed. Both figures are true; only one belongs in a specification.

Line 2: Minimum pressure — the line that sinks projects

A basin mono mixer typically carries a working range such as 0.5–5 bar, sometimes 1.0–5 bar, with a PN 10 body rating under EN 817. Below the minimum, the symptom is not a leak but a complaint: the lever feels vague, temperature control becomes imprecise, and flow at the spout drops to a trickle.

Match the minimum to the system, not the brochure:

• **Tank-fed gravity systems** in older buildings often deliver 0.2–0.4 bar at an upstairs basin. A 0.5 bar minimum mixer is the wrong product regardless of how it looks.
• **Mains-pressure and combination-boiler systems** normally run 1.5–3 bar and suit any standard mixer.
• **High-rise or boosted systems** can exceed 5 bar at lower floors. Above the rated maximum, fit a pressure-reducing valve; a cartridge is not a regulator.

Ask for both figures in writing: minimum *and* maximum working pressure.

Line 3: Cartridge size and type

"35 mm ceramic cartridge" is the standard entry for a basin mono; 40 mm appears on larger bodies and some kitchen mixers. The diameter determines body size and whether a replacement exists in five years.

A complete line reads something like: *35 mm ceramic disc cartridge, flat base, 90° rotation, with non-return valves.* Each element is a purchasing decision:

• **Base profile** — flat, stepped or lugged; a flat-base cartridge will not seal in a stepped seat.
• **Rotation angle** — 90° is common on basin mixers; 45° quarter-turn suits accessible and care environments.
• **Non-return valves** — relevant to EN 1717 backflow protection where the supply arrangement requires it.
• **Spare part reference** — the single most useful field for a maintenance team. A cartridge without a part number is a mixer with a service life of one cartridge.

Line 4: Inlet connections

Connection codes are where ordering errors originate. The common configurations:

• **G 1/2" BSP male** on flexible tails — the default in the UK, Middle East and much of Asia.
• **G 3/8"** — common in continental European installations; a 1/2" tail will not fit a 3/8" isolator without an adaptor, and the adaptor adds 15 mm of stack height.
• **M10 × 1** — the fine thread at the top of a flexible hose where it joins the mixer body, usually paired with a G 1/2" nut at the wall end.

Also check hose bore and length. An 8 mm bore tail flows noticeably better than 6 mm on a low-pressure system, and a 350 mm tail will not reach isolators mounted low in a vanity. State the required length; do not assume.

Line 5: Dimensions that decide fit

Spout reach, spout height, body diameter, tap hole diameter (usually 35 mm), deck thickness range and overall height beneath the deck. A datasheet without a dimensioned drawing is a picture, not a specification. Confirm deck thickness against the worktop — a 40 mm solid-surface upstand often exceeds a 30 mm-rated mixer.

Line 6: Compliance claims

Standards should be named with scope. EN 817 covers mechanical mixers rated PN 10; EN 248 covers the coating; EN 246 covers flow regulators. WRAS indicates UK approval for water fittings; NSF/ANSI 61 covers drinking-water system components and NSF/ANSI 372 the 0.25% weighted-average lead limit for wetted surfaces. A claim of "NSF approved" without a certificate number and a listing reference is marketing, not compliance.

What each number does — and does not — tell you

Seven questions to send back to the supplier

At what pressure was the flow rate measured, and was the aerator fitted?

What are the minimum and maximum working pressures?

What is the cartridge diameter, base profile and spare part number?

What are the inlet thread, hose bore and hose length?

What is the deck thickness range, and is there a dimensioned drawing?

Which standard and which certificate number support the compliance claim?

What is the declared noise group, if the project is a hotel or residential block?

A supplier who answers all seven in one email is a supplier worth keeping. The rest is arithmetic.

*Written by the technical sales team at Zhejiang Xindong Sanitary Ware Co., Ltd., a manufacturer of brass basin mixers and wall-mounted basin mixers (T749002, T713002, T8802, T7502, T7102, T730022) supplying importers, distributors and specifiers. Datasheets and dimensional drawings: www.cn-xindong.com.*