Common Plumbing Materials and Jointing Processes

Common Plumbing Materials and Jointing Processes

• Various methods exist for joining plumbing materials, including copper, plastic, and others. These methods differ in their procedures and materials involved.

LCS Fittings

• Threaded: Joints use BSPT threads, along with PTFE or hemp/paste for a watertight seal.
• Compression: These use a tapered rubber seal for a watertight connection.
• Unions: Usually have flat or conical faces for creating a watertight seal.
• Flanges: Employ rubber or fibre gaskets for watertight seals in flat-face joints.

Tap Connectors

• Connect supply pipework to tap/float-operated valves.
• A fibre washer is used to create a watertight seal.

Flexible Connectors

• Facilitate connecting pipework or appliances with waste pipes.
• Typically 300mm long, some include internal isolators.

Manifolds

• Allow a single pipe to be divided into several pipes (e.g. microbore, underfloor heating).
• Conversely, several pipes can be connected to a single main pipe (e.g. waste pipes).

Tank Connectors

• Create supply points from cisterns, like for cold water distribution.
• Employ rubber and neoprene washers for watertight seals.

Plastic Push-Fit Fittings

• These can connect plastic to copper or plastic to plastic.
• Pipe ends must be cut square and burr-free.
• Sleeves/inserts support plastic pipes.
• An O-ring creates a watertight seal.
• Silicon gel aids insertion and lubrication.
• Reusable fittings often require tools for removal.

Plastic Compression Fittings (Mechanical)

• Connect copper or plastic pipes.
• Seals/O-rings are crucial for watertightness.
• Burrs on the pipes must be removed.
• An integral support ring is placed behind the seal.

Plastic Solvent Weld Fittings

• Used for ABS and uPVC waste/soil pipes.
• Surfaces are cleaned, and solvent cement is applied.
• Components are joined and chemically melt together.
• Joints cure within minutes.

Plastic MDPE Fittings

• Allow plastic-to-plastic connections (can also be used in combination with copper or screw-thread LCS).
• Can be push-fit, compression, or fusion-welded.

Solder-Ring Fittings

• The pipe and joint are cleaned.
• Flux is applied.
• Solder is in an integral ring.
• Heat is applied to allow the solder to flow.
• The joint is allowed to cool.
• The joint is wiped clean with a cloth.

Push-Fit Fittings

• Suitable for pressure plastic or copper pipes.
• Pipe ends must be cut square and burr-free.
• O rings create a watertight seal.
• Sleeve or insert supports plastic pipes.
• Lubrication (e.g. silicon gel) can assist installation.

Compression Fittings (Type A)

• Non-manipulative fittings.
• Require square cutting and burr removal; an olive is used; the fitting is tightened using an adjustable wrench.
• Suitable for half-hard copper and plastic pressure pipe.

Compression Fittings (Type B)

• Manipulative fittings.
• Involve using a swaging tool.
• More durable than Type A but cannot be separated without the tool.
• Often used for high and below ground pressure pipe work.

Brass Fittings

• An alloy of copper and zinc.
• Can suffer from dezincification, creating a white powdery zinc oxide coating, and making the fitting brittle.
• Modern fittings are marked CZ or DZR to indicate dezincification resistance.

Press-Fit Fittings

• An O-ring is used to create a watertight seal.
• Components are pushed into place.
• Then clamped into position using a mechanical tool.

Lead Pipe Considerations

• When lead pipe is discovered, it is typically advised to remove it.
• Specialised fittings (e.g., leadlock) can sometimes be used for carefully connecting other pipes to an existing lead pipe.
• The standard "wiped joint" is no longer permitted.

Materials for Joints (Copper, Steel, Plastic)

• Flux: Active fluxes (acid-based) aid solder flow, passivate, and prevent oxidation. Non-active fluxes (paraffin-based) are used for cleaning pipes.
• PTFE Tape/String: Used on threads of low carbon steel pipes for a watertight seal.
• Hemp/Paste: Alternatively, hemp and paste are placed onto the threads of the pipe.
• Gaskets: Rubber and fiber gaskets are employed in flange-faced joints.
• Solvent Weld: Used on plastic waste/soil pipes.
• Rubber Seals (silicon): Used for seals, especially on plastic waste/soil pipes.
• O Rings: Used in push-fit, waste/soil piping.

Hazards

• Potential for burns to people and property.

• Fires.

• Explosions.

• Oxidation from flux.

• Pitting.

• Fumes from soldering and solvent welding.

• Earthing is crucial for metallic pipes. This includes equipotential, supplementary, and temporary continuity bonding.

• Metallic tape is required to track all hidden plastic pipework behind walls.

Quality Assurance

• WRAS approval, British Standard kite mark, and BBA approval are crucial for all components in installations.
• BRE Building Research Establishment and IOPHE offer advice and guidance.

True/False Questions and Answers

• Compression fittings have olives: TRUE.
• End feed fittings have a solder ring: FALSE.
• Can I use solder with Push Fit Fittings? NO.
• Press-fit fittings have O rings: TRUE.