Plumbing and Sanitary Installation Inspection

Per DTU 60.1 (NF P 40-201), water supply installations must use approved materials (copper per NF EN 1057, PER/PEX per NF EN ISO 15875, or multilayer per NF EN ISO 21003) with proper sizing per DTU 60.11. Pipes must be routed to avoid freezing, properly supported at specified intervals, and equipped with isolation valves at each branch and appliance.

1. Verify that pipe materials carry the NF or equivalent certification mark and are listed in DTU 60.1 as approved for potable water supply

2. Check pipe sizing calculations per DTU 60.11 to confirm adequate flow rates at the most remote fixtures (minimum 0.20 l/s at a tap)

3. Confirm that isolation valves are installed at the main entry, each branch, and each appliance as required by DTU 60.1

4. Verify that pipe supports are at the intervals specified in DTU 60.1 (e.g., every 1.3 m for 16 mm PER pipes, every 1.5 m for 20 mm copper)

5. Check that pipes in unheated areas or exterior walls are insulated against freezing per DTU 60.1 requirements

- Pipe diameters undersized, causing poor flow at remote fixtures and pressure drops below the 1 bar minimum

- Missing isolation valves at branch points, preventing localised maintenance

- Pipes routed through uninsulated spaces without freeze protection

- Incompatible fittings used at transitions between different pipe materials

- Pipe supports missing or spaced too far apart, causing sagging and stress at joints

Per DTU 60.32 (NF P 41-213), drainage installations must be designed to convey waste water efficiently with minimum gradients of 1% for horizontal runs (3% preferred for branch connections). All waste pipes must be vented to prevent siphoning of traps. Pipe materials must comply with NF EN 1329 (PVC-U) or NF EN 1451 (PP). Traps must maintain a minimum water seal of 50 mm.

1. Verify that horizontal waste pipe gradients are at least 1% (1 cm per metre) and branch connections achieve 3% where specified per DTU 60.32

2. Confirm that all sanitary appliances are fitted with traps providing a minimum 50 mm water seal per NF EN 274

3. Check that vent pipes are correctly installed — either individual vents, branch vents, or an air admittance valve conforming to NF EN 12380

4. Verify watertightness by running a visual inspection under flow conditions and checking all joints and connections for leaks

5. Confirm that pipe diameters match the connected appliance requirements per DTU 60.32 (e.g., 40 mm minimum for wash basin, 100 mm for WC)

- Insufficient gradient on horizontal runs, leading to slow drainage and blockages

- Missing or inadequate venting, causing trap siphonage and odour ingress

- Incorrect pipe diameters at connections, particularly WC branches using less than 100 mm pipe

- Push-fit joints not fully seated, causing slow leaks at connections

- Traps with water seals below 50 mm, allowing sewer gases into occupied spaces

Per French regulation (Arrêté du 30 novembre 2005) and DTU 60.1, hot water systems must be designed to prevent Legionella proliferation. Storage water heaters must maintain water at a minimum of 55°C (60°C recommended) at the base of the tank. Distribution must deliver water at 50°C minimum at the furthest point within 30 seconds for systems exceeding 3 litres of dead leg volume. A recirculation loop is mandatory for buildings where the volume between the production point and the furthest draw-off exceeds 3 litres.

1. Measure stored hot water temperature at the base of the tank — must be at least 55°C, with the thermostat set to 60°C or above

2. Check delivery temperature at the furthest draw-off point — must reach 50°C within 30 seconds of opening the tap

3. Verify that a recirculation loop is installed and functioning where the dead leg volume exceeds 3 litres per regulation

4. Confirm that anti-scald mixing valves (NF EN 15092) are fitted at points of use, limiting delivery to 50°C at wash basins and 38°C at baths per NF DTU 60.1

5. Review the maintenance log for evidence of periodic thermal shock treatment (raising temperature above 70°C) where required

- Hot water storage temperature set below 55°C, creating conditions for Legionella colonisation

- Recirculation loop absent or not functioning, leaving stagnant water in long pipe runs

- Anti-scald valves missing at points of use, creating burn risk particularly in bathrooms

- Dead legs exceeding 3 litres not identified during design, resulting in stagnant sections

Per DTU 60.1, pipes must be supported at specified intervals depending on material and diameter. Hot water pipes and pipes in unheated spaces must be insulated per RE 2020 energy requirements. Pipe routing must allow for thermal expansion and avoid contact between incompatible materials.

1. Verify pipe support spacing — copper: maximum 1.2 m horizontal / 1.8 m vertical; PER/PEX: maximum 0.7 m horizontal per DTU 60.1

2. Check that hot water pipes are insulated with minimum Class 2 insulation per RE 2020 requirements

3. Confirm that cold water pipes in unheated spaces are insulated against frost (minimum 13 mm insulation)

4. Verify that expansion loops or sliding supports are provided on long copper runs per DTU 60.1

5. Check that pipes passing through walls or floors use sleeves (fourreaux) and are not in direct contact with the structure

- Insufficient pipe supports causing sagging and stress at joints

- Missing insulation on hot water pipes, increasing energy losses beyond RE 2020 limits

- No expansion provision on long copper runs, causing stress and joint failure

- Pipes passing through structure without sleeves, preventing movement and causing noise

Per NF EN 806-4 (commissioning of water installations) and DTU 60.1, all water supply pipework must be pressure tested before concealment and before commissioning. The test pressure must be at least 1.5 times the maximum operating pressure, with a minimum of 10 bar, maintained for a minimum duration without pressure drop. Drainage systems must be tested for watertightness per DTU 60.32.

1. Confirm that the pressure test was carried out before pipework was concealed (before plastering, screeding, or cladding)

2. Verify the test pressure applied — minimum 1.5 times the maximum working pressure or 10 bar, whichever is greater, per NF EN 806-4

3. Check the test duration — pressure must be maintained for a minimum of 10 minutes with no visible drop on the gauge per NF EN 806-4 procedure

4. Review the pressure test certificate, which must record the date, pressure applied, duration, and result (pass/fail)

5. For drainage, verify that a water test or air test was performed per DTU 60.32 to confirm watertightness of all joints

- Pressure test not performed before pipework was concealed, making leak detection impossible

- Test pressure insufficient or duration too short to reveal slow leaks at joints

- No written test certificate available, preventing verification of compliance

- Drainage joints not tested, leading to slow leaks discovered only after floor finishes are installed

Per NF EN 1717, potable water supplies must be protected against backflow contamination by installing appropriate backflow prevention devices matched to the fluid category risk. Each connection point must be assessed for the contamination risk level (categories 1-5), and the correct type of backflow preventer installed. DTU 60.1 requires a type EA disconnector (controllable backflow preventer) at the building entry for collective installations.

1. Verify that a backflow prevention device is installed at the building's water supply entry point — typically a type EA controllable disconnector per DTU 60.1

2. Check that each appliance connection has the appropriate level of backflow protection per NF EN 1717 risk assessment (e.g., type AA air gap for category 5 risks)

3. Confirm that filling loops for closed heating circuits are fitted with a type BA disconnector or equivalent per NF EN 1717

4. Verify that outdoor taps and irrigation connections have at least a type HA (hose connection backflow preventer) or higher protection

5. Review maintenance records for annual testing of mechanical backflow prevention devices as required by regulation

- No backflow preventer at the building entry point, leaving the public supply at risk

- Filling loops for heating circuits left permanently connected without a disconnector

- Outdoor hose connections without any backflow protection, risking contamination from garden chemicals

- Mechanical backflow preventers not tested annually, with seized or failed check valves going undetected

Per DTU 61.1 (NF P 45-204), gas installations must comply with strict requirements for pipe materials, routing, ventilation, and safety devices. Copper (NF EN 1057) or steel (NF EN 10255) pipes are used internally, with PE pipes (NF EN 1555) for buried external runs. All gas installations require a tightness test before commissioning and must be certified by a Qualigaz-accredited inspector. Ventilation openings must be provided per DTU 61.1 for combustion air supply.

1. Verify that gas pipe materials are approved per DTU 61.1 — copper or steel internally, PE for buried external sections, with no PVC or unapproved materials

2. Check that a gas isolation valve (robinet de barrage) is accessible at the building entry and at each appliance

3. Confirm that the tightness test has been performed — pressurised to 1.5 times working pressure (minimum 50 mbar for low-pressure systems) for at least 10 minutes with no pressure drop

4. Verify that combustion air ventilation openings are correctly sized per DTU 61.1 for the appliance type and rating (e.g., 50 cm² per kW for open-flue appliances)

5. Check that the Qualigaz certificate of conformity (certificat de conformité) has been obtained before gas supply is connected

- Tightness test not performed or not documented, preventing gas supply connection

- Combustion air ventilation openings undersized or blocked, creating carbon monoxide risk with open-flue appliances

- Gas pipes routed through bedrooms or bathrooms without meeting the specific safety conditions of DTU 61.1

- Missing Qualigaz certificate, delaying gas connection by the distribution network operator

- Flexible connections (ROAI) used beyond their maximum length or without being accessible for inspection