Isolation Valve Selection for a Building: Which Tier Shuts Down What

The International Plumbing Code names eight locations in a building where a full-open valve is required, and only three where a plain shutoff valve will do. Most valve schedules never make that distinction. They list "isolation valve" against every branch on the riser diagram and let the contractor decide what arrives on site — which is how a restricting valve ends up at the base of a riser serving nine floors.

This page maps isolation to the building instead of to the valve catalogue. Five tiers, from the service entry down to the fixture stop: which code clause puts a valve at each one, what type belongs there, and — the question a facilities manager actually asks — how much of the building loses water when you close it.

Isolation Valve vs Shutoff Valve: The Code Distinction That Decides Your Schedule

"Isolation valve" is a job description, not a product category. The code splits that job in two, and the split is where specification errors start.

Section 606.1 of the International Plumbing Code covers full-open valves — valves whose open position leaves the waterway essentially unrestricted. It names eight locations:

1. The building water service pipe from the public water supply, near the curb.
2. The water distribution supply pipe at the entrance into the structure.
3. The discharge side of every water meter.
4. The base of every water riser pipe, in occupancies other than multiple-family residential of two stories or less and other than one- and two-family residential.
5. The top of every water down-feed pipe, in occupancies other than one- and two-family residential.
6. The entrance to every water supply pipe to a dwelling unit, except where it supplies a single fixture equipped with individual stops.
7. The water supply pipe to a gravity or pressurized water tank.
8. The water supply pipe to every water heater.

Section 606.2 covers shutoff valves, and the list is much shorter. Three locations: the fixture supply to each plumbing fixture (other than bathtubs and showers in one- and two-family dwellings, and other than individual sleeping units already provided with unit shutoff valves in hotels, motels and similar occupancies); the water supply pipe to each sillcock; and the water supply pipe to each appliance or mechanical equipment.

Read the two lists side by side and the logic appears

Every 606.1 location sits on a pipe that feeds other pipes. Every 606.2 location sits at the end of a run, feeding one thing. That is the whole rule. Distribution gets full-open; termination gets a stop.

The reason is hydraulic, not bureaucratic. A valve on a distribution main is open for its entire service life apart from a few hours a decade, so any restriction it introduces is a permanent tax on every fixture downstream — paid every day, forever, to buy nothing. A fixture stop restricts one basin, and the basin's own aerator restricts it far more.

Where "isolation" and "stop" stop being interchangeable

Terminology drifts by market. British and European practice tends to say stop valve or servicing valve; North American code says full-open and shutoff; contractors on both sides say isolation valve for all of it. When a specification crosses a border, that ambiguity travels with it.

The defence is to write the requirement, not the nickname. A line that reads "isolation valve, DN50" can be honoured with anything. A line that reads "full-open valve to IPC 606.1(4), full bore, DN50" can only be honoured one way. If you take one habit from this page, take that one.

The Five Isolation Tiers in a Multi-Storey Building and What Each One Shuts Down

Code tells you where valves are required. It does not tell you what closing one costs you in tenant complaints. That calculation is the real design decision, and it runs across five tiers.

Tier 1 — Service entry and meter: the whole building

IPC 606.1 puts full-open valves at three points here: near the curb on the service pipe, at the entrance into the structure, and on the discharge side of the meter. Closing any of them stops water to every fixture on the site.

This tier gets used perhaps twice a decade, which is exactly why it fails when needed. A valve that has not moved in eight years is a valve nobody has confirmed still moves.

Tier 2 — Riser base and down-feed top: one vertical stack

This is the tier that separates a competent riser diagram from a careless one. IPC 606.1(4) requires a full-open valve at the base of every water riser in occupancies above the two-storey residential threshold; 606.1(5) requires one at the top of every down-feed pipe in occupancies other than one- and two-family residential.

The down-feed clause is the one specifications forget. In a tower where water is pumped to a roof tank and falls back down, the top of the down-feed is the isolation point — and a valve at the bottom of that pipe isolates nothing useful, because gravity keeps the column charged above it.

Some jurisdictions go further than the model code. Massachusetts (248 CMR 10.14) requires that "a full-port valve shall be installed at the base of each water supply riser when servicing multiple fixtures on levels above the first floor," and adds a requirement the model IPC does not state: "a draw off valve shall be installed upstream of each riser valve." The same section requires that branch valves serving multiple fixtures be full port, and that in multistory buildings a full-port valve be installed at the top of each supply pipe upstream from a booster system.

That drain requirement deserves attention even where it is not mandatory. A riser you can close but not drain is a riser you cannot work on — the water has to leave the pipe before a fitter can open it, and without a drain point it leaves through whichever fixture is lowest, usually into an apartment.

Tier 3 — Floor or zone branch: one level

Model IPC does not mandate a valve at every floor take-off; local amendments frequently do. Philadelphia's P-810.3 requires that "separate valves, readily accessible, shall be placed at the foot of each riser line, on all branches to exterior hose bibbs, on hot water storage tanks, and on supplies to fixtures."

Even where no clause forces it, floor-level isolation is usually the best value in the whole schedule. It is the difference between a leak on level 6 taking out level 6, and the same leak taking out the entire stack from level 1 to the roof.

Tier 4 — Dwelling entry: one apartment

IPC 606.1(6) requires a full-open valve at the entrance to every water supply pipe to a dwelling unit, with one exception: where that pipe supplies a single fixture equipped with individual stops. In practice the exception almost never applies in residential work, because an apartment has a kitchen and a bathroom.

This valve does double duty. EN 806-5:2012 Clause 7 recommends that "to avoid potential damage by water and water loss in the event of prolonged absence, ... the system is isolated at the supply stop valve in residential units and in the case of apartments, at the stop valve in the pipe entering the apartment." It is both the maintenance isolation point and the one an occupant is told to use before a long trip — so its accessibility is not a detail.

Tier 5 — Fixture stops and appliances: one outlet

Governed by IPC 606.2, not 606.1: a shutoff valve on each fixture supply, each sillcock, and each appliance or mechanical equipment connection. Full-port construction is not required here, and specifying it wastes money at the highest unit count in the building.

Read the middle column downward and the design rule states itself: every tier you leave out pushes its work up to the tier above, and the tier above always has a wider outage radius. Omit floor branch valves and a tap washer on level 6 becomes a stack shutdown. Omit dwelling-entry valves and it becomes a floor shutdown for every unit on that level.

The Valve Schedule: Tier, Code Basis, Valve Type and Port Requirement

Here is the schedule those five tiers produce. It is written to be lifted into a specification document and edited against your own jurisdiction.

Which standard actually governs the valve you receive

For ball valves in building potable water, the reference is EN 13828 — "Building valves. Manually operated copper alloy and stainless steel ball valves for potable water supply in buildings. Tests and requirements." Check the edition. BS EN 13828:2025 was published on 28 February 2025 and superseded BS EN 13828:2003, which is now withdrawn. A specification template written five years ago still cites the withdrawn edition, and so does a good deal of supplier literature.

The current scope covers DN 6 to DN 100 at PN10 or PN16, for a maximum distribution temperature of 65 °C, with occasional excursions up to 90 °C permitted for a period of 1 h maximum. Those two temperature figures are the ones to carry into a hot-water schedule — a valve qualified to this standard is not qualified for continuous duty above 65 °C.

Gate valves are the trap. EN 12288:2010 is an industrial valve standard — copper alloy gate valves for general use, DN 8 to DN 500, in pressure designations from PN 6 to PN 63 and Classes 150 and 300. It is not a building potable-water performance standard, and it says so itself: for specific applications such as drinking water, valves to that standard can be used "provided the requirements of the relevant performance standards are met," and approval by the relevant regulatory body may be required.

So "conforms to EN 12288" on a submittal answers a question you did not ask. For a potable application you also need the performance standard and, depending on the market, the regulatory approval — worth confirming with the local authority before the submittal is accepted.

What to check before the schedule goes out for quotation

Six checks before the schedule leaves your desk. Each one closes a gap that a supplier would otherwise have to guess at, and a guess on a submittal becomes a variation on site:

• Every line states full-open or shutoff, referencing the clause, not the word "isolation".
• Every hot-side line states a temperature duty against the 65 °C continuous ceiling and the 1 h / 90 °C excursion allowance.
• Every standard carries its edition year — and EN 13828 reads 2025, not 2003.
• Down-feed risers have a valve at the top, not only at the bottom.
• Riser valves have a drain point, whether or not your jurisdiction copies the Massachusetts wording.
• Local adoption is confirmed. The tier logic here is portable; the clause numbers are not. Verify against the code actually adopted in your project's jurisdiction — for export projects, confirm current requirements with the local authority or a consultant before issuing.

On material, the alloy is a separate decision from the tier, and it is one worth making deliberately — our note on CW617N lead-free brass covers where the dezincification and lead-content requirements bite. If you are pricing the schedule, the valve price benchmark guide explains what drives the number per unit. And the site's product catalogue lists the Brass Valves category, all in CW617N lead-free brass.

What Goes Wrong After Handover: Throttled Valves, Stagnation and the 7-Day Rule

A correct schedule installed correctly still degrades, and the European operating standard is unusually specific about how. EN 806-5:2012 governs operation and maintenance of potable water installations inside buildings, and several of its clauses read like a list of the things buildings actually get wrong.

Fully open or fully closed — never in between

Clause 6 states it plainly: "Stop valves and servicing valves shall always be in their fully open or closed position and actuated at regular intervals to ensure they remain operational."

Two requirements sit in that sentence. The first bans throttling: a valve is not a flow regulator, and using one to trim a branch puts the closure element permanently in the flow path where it erodes. The second is the one buildings skip — actuated at regular intervals. An isolation valve that is never exercised is a valve whose condition is unknown, and the moment you discover it is the moment you need it.

The standard treats a partly-closed valve as a fault with symptoms. Clause 9.2 lists causes of insufficient water supply, and the first entry is "stop valves not fully opened." Clause 9.3 lists causes of excess noise, including "stop valves that are defective or not fully opened" and water hammer "caused by rapid-closing or defective draw-off fittings, unsuitable valves, incorrect operation or installation or inadequate fixing." So the throttled valve on level 6 turns up twice in the fault tree: once as a pressure complaint, once as a noise complaint. Buildings usually chase both symptoms separately.

The 7-day rule, and why fit-out programmes breach it

Clause 7 sets a threshold most projects never check against their own programme: "Installations, which will not be operated within 7 days of their completion or are out of service for more than 7 days, shall either be shut off at the supply stop valve and drained or the water shall be flushed regularly."

Consider what that means on a residential tower. Plumbing is pressure-tested and completed floor by floor, then the building waits for finishes, lifts, inspection and handover — routinely months. Under this clause, water standing in those pipes is not a neutral state: it either gets shut off and drained, or it gets flushed on a schedule. Clause 9.1 names the reason directly, noting that where water stagnates and temperature falls outside EN 806-2 limits, "there is an increased risk of bacteria growth, e.g. Legionella."

The tier design decides how expensive compliance is. With floor and dwelling-entry valves in place, you can drain the completed section and leave the rest live. Without them, the choice is draining a whole stack or flushing every outlet on it.

The same clause adds a longer threshold for the service side: pipes not commissioned immediately after completion or temporarily disconnected "shall be shut off at the water main," and those unused "for a period of one year or more, should be disconnected from the water main."

Bringing it back without hammering the system

Reopening is a sequence, not a handle-turn. Clause 8 requires that stop valves "be partially opened, starting with the service stop valve," then the pipes "completely vented by slowly opening the taps," and only after that are the stop valves fully opened and the pipes flushed. Skip the partial-open step on a large drained riser and you drive a column of air and water into fittings at speed.

For a short interruption the standard is more relaxed: opening individual draw-off fittings fully "for a short period (approximately 5 min)" is usually enough to let stagnant water run off.

The valve you cannot reach is a valve you do not have

Clause 11 requires that components needing regular inspection and servicing, "and all controls (e.g. on stop valves) shall be readily accessible for inspection, maintenance and operation," with access "not obstructed by stored goods, furniture, cladding, floor coverings, etc."

Every one of those obstructions arrives after handover, from someone who does not know a valve is there. Access panels get tiled over; risers become storage. This is worth designing against rather than writing into an O&M manual nobody reads.

What the standard does not give you

EN 806-5 Annex A is normative and Table A.1 sets inspection and routine maintenance frequencies across 46 component types. Some examples: pipework, once a year. Pressure reducing valves to EN 1567, inspection once a year and routine maintenance once a year. Backflow preventers with controllable reduced pressure zone to EN 12729, inspection every 6 months and routine maintenance once a year. Non-controllable antipollution check-valves to EN 13959, inspection once a year with replacement every 10 years. Cold water meters, inspection once a year and routine maintenance every 6 years; hot water meters, every 5 years.

Table A.1 does not list a frequency for plain stop or isolation valves. That absence is worth stating rather than papering over, because it is where invented numbers enter specifications. The standard's own fallback is Clause 12: routine maintenance on stop valves is carried out in accordance with the manufacturer's instructions, and Clause 6 independently requires that they be actuated at regular intervals. Set the interval against the manufacturer's documentation and your own risk assessment — the standard also allows that frequencies may be adjusted for network size and complexity, type of water use, user vulnerability, and whether operation is permanent or seasonal, provided any deviation is justified and recorded.

One point on valve type belongs here, stated as a direction rather than a number. Because a gate valve seals on a wedge that travels through the flow path, trade practice holds it is more vulnerable to scale and debris preventing full closure, while a quarter-turn ball valve has no rising stem to seize. That is a well-attested tendency rather than a measured figure, and it does not override the schedule above.

It does explain why quarter-turn hardware suits the tiers that get operated often. For the comparison itself, we treat it head-on in brass ball valve vs gate valve, and the gate-valve variants — NRS, OS&Y, resilient-seated — are covered in gate valve types.

Ordering Against the Schedule: One Building, Five Valve Roles, One Shipment

A tier-based schedule creates a procurement problem the moment it is finished. One building now needs full-bore valves in larger bores at the risers, mid-size valves at dwelling entries, compact stops at hundreds of fixtures, and probably valved manifolds at the zone branches. Different sizes, different handles, different quantities — and traditionally different suppliers, each with its own minimum.

What to put in the first email

Send the schedule itself rather than a size list. A manufacturer quoting from tiers can propose one component where you wrote two, and can flag where a duty is outside a standard's scope. For each tier, state the six things that actually determine the quote:

• Size range and quantity per tier — not a total valve count.
• Full-open or shutoff, with the clause reference.
• Pressure class and temperature duty, hot and cold separately.
• Connection type per tier — threaded, compression, or a transition to the pipe system in use.
• Standard and edition, plus any market approval your jurisdiction requires.
• Handle type and marking where maintenance access or position indication matters.

Minimums, verification and what to settle before the container ships

At IFAN the minimum order is one container, and it can be mixed across sizes and product lines, with pipe, fittings, valves and accessories in the same load. For a five-tier schedule that structure matters more than a unit price: it is what lets one order cover the whole building rather than five separate minimums. Pricing is quoted per SKU against the schedule rather than published as a list, and the stated turnaround for a factory quote is 12 hours.

Settle the verification route in the same conversation, because it is the step that catches a mismatch while it is still cheap. Ask what physical verification is available for each tier before you commit, and put in writing what you intend to check — thread fit against the pipe system actually specified, body marking, and handle clearance in the real riser cupboard. Lead time is set per project against the size mix rather than published as a fixed figure, so ask for it against your own quantities rather than in the abstract.

Two verification steps are worth taking before a container leaves. Check the body marking against what the schedule asked for — size and pressure class cast into the body, as in the valves pictured above, rather than a printed label that survives one wash. And confirm the standard edition on the documentation, since a certificate citing EN 13828:2003 is citing a withdrawn document.

The company behind this schedule advice manufactures the hardware: IFAN has run its factory since 1993, operates a 120,000m² facility in Zhejiang with an in-house injection moulding and mould workshop, and exports to 120+ countries. Valve configuration work — including tailored valve configurations in lead-free brass — runs through the manufacturing and OEM side of the business.

How the body is formed, and why it decides whether the marking means anything

Everything above assumes the valve arriving on site matches its marking. Forming method is what decides that. Brass valve bodies are cold-forged and then precision-machined: forging compacts the grain structure and leaves a dense body, and the machining that follows sets the seat geometry the closure element has to match. A cast-in DN or PN marking is only as trustworthy as the consistency of that route — which is why a body marking cast into forged brass carries more weight than a printed label, and why it is worth seeing the production sequence before signing off on a tier that will never be re-piped.

Where this page hands off

This article deliberately stops at the tier. The decisions one level down have their own pages: brass ball valve sizes for the DN selection inside a tier, flanged vs threaded connections for how the valve meets the pipe at larger bores, and types of valves for the wider roster including the pressure and backflow devices that share a plant room with these.

Two of those devices interact with your isolation design and are worth reading alongside it: a pressure reducing valve needs isolation either side to be serviceable at the annual frequency Table A.1 sets, and a backflow preventer carries a six-month inspection requirement that a buried installation makes impossible to meet.

Your next three steps

1. Mark up the riser diagram by tier, then write the outage radius beside each valve. Any tier whose radius is wider than the work it will serve is a missing valve one level down.
2. Rewrite every "isolation valve" line as full-open or shutoff with its clause reference, its edition-dated standard, and its temperature duty.
3. Confirm local adoption of the clauses you cited, then send the schedule for quotation as one package rather than as separate size lists.

Frequently Asked Questions