Plumbing Inspection

Per EN 806-2 (design) and EN 806-4 (installation), water supply piping must be designed and installed to deliver adequate flow rates and pressure at all outlets. Pipe materials must be appropriate for the water quality and operating temperature: copper pipes per EN 1057, or plastic pipes per EN ISO 15874 (polypropylene), EN ISO 15875 (crosslinked polyethylene PEX), EN ISO 15876 (polybutylene), or EN ISO 15877 (chlorinated PVC). All materials in contact with drinking water must comply with national hygiene requirements.

1. Verify pipe material and dimensions match the design specification and are certified to the relevant EN/EN ISO standard

2. Check that pipe routing avoids dead legs — maximum dead leg length of 3 litres volume per EN 806-2

3. Confirm pipe connections are made correctly — soldered (copper), press-fitted, or fusion-welded (plastic) as specified

4. Verify pipe labelling and traceability — pipes must bear manufacturer mark, standard number, and dimension

5. Check that hot and cold pipes are separated by minimum 25mm or insulated to prevent heat transfer

- Dead legs exceeding maximum volume, creating stagnation and Legionella risk

- Wrong pipe material for the water conditions (e.g., copper in aggressive water without inhibitor)

- Connections not properly made, creating potential leak points

- Hot and cold pipes in contact, causing unwanted heat transfer and condensation

Per EN 12056-1 to EN 12056-5, gravity drainage systems inside buildings must be designed with adequate pipe sizes, gradients, and venting to ensure self-cleansing flow without siphonage of traps. EN 12056-2 covers wastewater drainage, EN 12056-3 covers roof drainage, and EN 12056-4 covers effluent pumping stations. Pipe gradients must be between 1% and 4% for horizontal drainage runs (1:100 to 1:25) to maintain self-cleansing velocity.

1. Verify pipe sizes match the design calculated per EN 12056-2 for the connected fixture units

2. Check pipe gradients with a spirit level or laser — minimum 1% (1:100) for pipes 100mm and above

3. Confirm all traps have minimum 50mm water seal depth per EN 12056-2

4. Verify ventilation provisions — vent pipes or air admittance valves per EN 12056-2 to prevent trap siphonage

5. Check that clean-out access points are provided at changes of direction and at maximum intervals per EN 12056-2

6. Confirm pipe supports are at correct spacing per pipe material and diameter

- Pipe gradients too shallow, causing slow drainage and blockages

- Pipe gradients too steep, causing water to outrun solids

- Traps with insufficient seal depth, allowing sewer gas into the building

- Inadequate venting, causing trap siphonage on simultaneous discharge

- Missing clean-out access points making future maintenance impossible

Per EN 806-2, hot water systems must be designed to deliver water at a minimum of 60 degrees Celsius at the storage vessel to control Legionella bacteria growth, while ensuring delivery temperature at outlets does not exceed safe limits (typically 48 degrees Celsius maximum at accessible outlets via thermostatic mixing valves). EN 1717 requires backflow prevention devices to protect the potable water supply from contamination by the hot water system.

1. Verify hot water storage temperature is set to minimum 60 degrees Celsius per EN 806-2 Legionella prevention

2. Check that thermostatic mixing valves (TMVs) are installed at accessible outlets to limit delivery temperature

3. Confirm hot water circulation system operates correctly — return temperature minimum 55 degrees Celsius

4. Verify expansion vessel or expansion relief is provided and correctly sized for the system volume

5. Check that hot water pipes are insulated per EN ISO 12241 to reduce heat loss and maintain temperatures

6. Confirm backflow prevention is installed per EN 1717 at the cold water connection to the hot water system

- Storage temperature below 60 degrees Celsius, creating Legionella growth conditions

- No TMVs installed at accessible outlets, creating scalding risk

- Circulation system not maintaining minimum return temperature

- Insufficient insulation on hot water pipes, causing excessive heat loss

- No expansion provision, creating dangerous pressure build-up

Per EN 806-4, pipe supports must be provided at intervals appropriate to the pipe material and diameter to prevent sagging, stress at joints, and noise transmission. EN ISO 12241 specifies calculation methods for thermal insulation of pipes, and insulation thickness must be sufficient to prevent heat loss (hot pipes), condensation (cold pipes), and freezing in unheated areas. Pipe supports must allow for thermal expansion and must not damage the insulation.

1. Verify pipe support spacing per EN 806-4 — typically 1.2m for 15mm copper, 0.6m for 15mm plastic horizontal runs

2. Check that supports are appropriate for the pipe material and do not cause abrasion or electrolytic corrosion

3. Confirm pipe insulation thickness meets EN ISO 12241 requirements for the application

4. Verify insulation is continuous through supports — no compression or gaps at support points

5. Check that insulation joints are taped or sealed to prevent moisture ingress and thermal bridging

6. Confirm expansion loops or offsets are provided at appropriate intervals for long straight runs

- Pipe supports too widely spaced, causing sagging and stress at joints

- Insulation missing or compressed at support points, creating thermal bridges

- Cold water pipes uninsulated in warm humid spaces, causing condensation dripping

- No provision for thermal expansion, causing stress and noise in the pipework

Per EN 806-4, completed water supply installations must be pressure tested before being put into service. The test pressure shall be 1.5 times the maximum design pressure (minimum 10 bar) held for a specified duration with no visible leaks and no pressure drop beyond allowable limits. EN 12056-5 specifies testing requirements for drainage systems including visual inspection, air testing, and water testing. All test results must be documented.

1. Verify pressure test is conducted at 1.5 times design pressure per EN 806-4 — minimum 10 bar

2. Confirm test duration meets requirements — typically 30 minutes for metal pipes, longer for plastic

3. Check that no pressure drop occurs beyond the allowable limit during the test period

4. Verify drainage system is tested per EN 12056-5 — air test or water test for above-ground drainage

5. Confirm all test results are documented with date, pressure, duration, and outcome

6. Verify system flushing and disinfection is performed before handover per EN 806-4

- Pressure test conducted at incorrect pressure or duration

- Slow leaks not detected due to test duration being too short

- Drainage testing omitted, leaving undetected leaks in concealed pipework

- System not flushed before handover, leaving debris and flux residue in pipes

- Test records incomplete or missing from handover documentation

Per EN 1717, backflow prevention devices must be installed to protect the potable water supply from contamination by backflow or back-siphonage. The standard classifies fluids into categories 1 (wholesome water) through 5 (lethal hazard) and specifies the required backflow protection device for each category. The type of device ranges from air gaps (Type AA, AB) for the highest risk to check valves (Type EA) for the lowest risk.

1. Identify all points of connection where potable water could be contaminated — each requires backflow protection per EN 1717

2. Verify the fluid category at each point of use is correctly assessed (categories 1–5)

3. Confirm the installed backflow device type matches the required protection level per EN 1717 Table 1

4. Check that air gaps (Type AA or AB) are provided where required — minimum air gap of twice the inlet diameter

5. Verify mechanical backflow devices are accessible for testing and maintenance

- Backflow protection missing at points of connection to non-potable systems

- Fluid category incorrectly assessed, resulting in inadequate protection

- Air gaps reduced by subsequent modifications (e.g., hose attached to tap)

- Mechanical backflow devices installed but not accessible for periodic testing

- No backflow protection at connection to garden irrigation or fire suppression systems

Per EN 1775, gas supply systems in buildings must be designed and installed to ensure safe and reliable delivery of gas to appliances. EN 15001-1 covers metallic gas pipework above 0.5 bar and up to 16 bar. All gas installations must be leak-tested before commissioning, and pipe materials must be compatible with the gas type (natural gas or LPG). Ventilation provisions for gas appliances must comply with EN 15287 (chimneys) and relevant national gas safety regulations.

1. Verify pipe material and joints comply with EN 1775 — typically steel, copper, or stainless steel with approved fittings

2. Check pipe sizing matches the design for the total gas demand of connected appliances

3. Confirm leak testing has been performed per EN 1775 — test at 1.5 times operating pressure for minimum 15 minutes

4. Verify gas meter and emergency shut-off valve are correctly located and accessible

5. Check ventilation provisions for gas appliances — combustion air supply and flue gas discharge per EN 15287

6. Confirm gas pipe identification markings and warning labels are installed per EN 1775

- Gas leaks at joints due to improper connection or testing

- Pipe undersized for the total gas demand, causing pressure drop at appliances

- Inadequate ventilation for gas appliances, creating carbon monoxide risk

- Emergency shut-off valve inaccessible or not identified

- Gas pipes passing through unventilated voids without adequate protection