Plumbing Systems & Piping

Plumbing is the circulatory system of every church building — sanitary drainage carries waste out, domestic water brings clean water in, storm piping manages the roof, and gas lines feed the mechanical equipment that keeps the congregation comfortable. From the underslab rough-in poured into concrete to the baptistry pool in the sanctuary, plumbing touches every part of a church project. This guide covers the core piping skills licensed plumbers and apprentices use daily on church construction sites across Ontario.

1. Copper Pipe Soldering & Brazing — Skill 7.01

Copper has been the gold standard for domestic water piping in Ontario commercial construction for decades. It’s durable, corrosion-resistant, and — when properly soldered — absolutely leak-proof. The two primary joining methods are soft soldering (below 450 °C) and silver brazing (above 450 °C), each with distinct applications governed by the Ontario Building Code (OBC Part 7) and CSA B214.

Soft Solder vs. Silver Braze

• Soft solder (95/5 tin-antimony or lead-free): Used for domestic water supply lines. Melts at approximately 230 °C. CSA B214 and OBC require lead-free solder on all potable water systems — no exceptions. This is the everyday joint for ½″ through 2″ copper supply piping.
• Silver braze (BAg-series alloys, 15% silver minimum): Used for medical gas, refrigeration, and high-temperature / high-pressure applications. Melts above 600 °C and produces a significantly stronger joint. Required by CSA Z7396.1 for medical gas systems and used on any joint that will see temperatures above 120 °C.

Joint Preparation Steps

1. Cut copper square using a tube cutter — never a hacksaw on supply piping (burrs compromise flow).
2. Ream the inside bore to remove the cutting ridge that restricts flow and creates turbulence.
3. Clean the outside of the tube and inside of the fitting with emery cloth or a fitting brush until bright copper is visible — no oxidation, no fingerprints.
4. Apply flux (water-soluble, lead-free per CSA B214) evenly to both surfaces. Flux prevents oxidation during heating and promotes capillary action.
5. Assemble, heat uniformly with a propane or MAP-Pro torch, and feed solder at the joint edge. Capillary action draws solder into the joint — the solder goes to the heat, not away from it.
6. Wipe excess solder with a damp rag while still molten for a clean, professional joint.

2. Steel Pipe Threading & Assembly — Skill 7.02

Black iron and galvanized steel pipe remain the backbone of gas piping, hydronic heating, and some drainage applications in commercial church construction. Every mechanical room on a church project has a forest of threaded black iron — gas trains to boilers, rooftop unit connections, and hydronic distribution headers. Threading is a fundamental plumbing skill that hasn’t changed much in a century, and there’s a reason: when done right, it works.

Threading Procedure

1. Measure and cut pipe square using a pipe cutter or band saw. A crooked cut produces crooked threads.
2. Ream the inside bore to remove the burr — an unreamed pipe restricts flow by up to 15% and creates sediment traps.
3. Secure pipe in the threading machine (RIDGID 300 Compact or 1224 for larger diameters). Verify the correct die head for pipe size.
4. Apply cutting oil generously and run the die at proper speed. NPT threads are tapered at 1:16 — the taper creates the seal as threads engage.
5. Thread to proper length: for ¾″ pipe, approximately 19 mm (10 threads); for 2″ pipe, approximately 25 mm (11 threads).
6. Apply pipe thread sealant (pipe dope or Teflon tape). For gas lines, use yellow Teflon tape (thicker, rated for gas) or CSA-approved pipe dope. Apply tape clockwise when facing the thread end — minimum 3 wraps.
7. Assemble by hand-tightening plus 2–3 full turns with a pipe wrench. Back-wrench the fitting to avoid torquing the entire assembly.

3. Plastic Pipe (PVC, CPVC, PEX, ABS) — Skill 7.03

Plastic piping has transformed commercial plumbing — lighter, faster to install, and corrosion-proof. But “plastic” isn’t one material; it’s a family of polymers with very different properties, joining methods, and code allowances. Understanding which plastic goes where is half the battle on a church project.

Material Applications

• ABS (acrylonitrile butadiene styrene): The standard DWV (drain, waste, vent) pipe in Ontario residential and light commercial. Black colour, solvent-welded joints. CSA B181.1. Lightweight and easy to work with, but not rated for pressure supply.
• PVC (polyvinyl chloride): Used for underground drainage, storm sewer, and some sanitary applications. White or green (for sewer). Solvent-welded. CSA B181.2. PVC Schedule 40 is the workhorse for underslab drainage on church projects.
• CPVC (chlorinated polyvinyl chloride): Rated for hot water supply up to 82 °C at 100 psi. Cream/gold colour. Solvent-welded with CPVC-specific cement (never use ABS or PVC cement on CPVC). CSA B137.6. Used in some commercial supply applications where copper cost is a concern.
• PEX (cross-linked polyethylene): Flexible tubing for hot and cold water distribution. Joined by crimp rings, expansion fittings (ProPEX), or push-fit connectors. CSA B137.5. Excellent for long runs through walls and ceilings — fewer fittings, fewer potential leak points.

Solvent Welding (ABS & PVC)

1. Cut square with a fine-tooth saw or ratchet cutter. Deburr and chamfer the pipe end.
2. Dry-fit and mark alignment — you have about 15 seconds of working time once cement is applied.
3. Apply primer (required for PVC; ABS uses one-step cement or primer per manufacturer). Primer softens the surface for chemical bonding.
4. Apply a full, even coat of cement to both pipe and fitting socket. Push pipe fully into fitting with a quarter-turn twist, then hold for 30 seconds.
5. Wipe excess cement. Allow cure time per manufacturer — typically 2 hours before pressure testing at 20 °C.

4. Cast Iron Pipe (No-Hub) — Skill 7.04

Cast iron pipe might seem like a relic, but walk into any well-built church and you’ll find it in the main sanitary stacks and horizontal storm drains. The reason is simple: noise reduction. A cast iron stack is whisper-quiet compared to ABS, and in a church where the sanctuary shares a wall with a washroom group, that silence is worth every dollar.

Cutting Methods

• Snap cutter (soil pipe cutter): The preferred method. A chain-style cutter wraps around the pipe and applies uniform inward pressure until the pipe fractures cleanly along the score line. Fast, square, and no sparks.
• Angle grinder with diamond blade: Used when a snap cutter won’t fit — tight spaces, wall penetrations, existing work. Produces a clean cut but generates dust, sparks, and noise. Wear respiratory protection (dust is siliceous) and eye protection per OHSA requirements.

No-Hub Coupling Assembly

1. Cut pipe square. File or grind any burrs that would prevent the neoprene gasket from sealing.
2. Slide the no-hub coupling (stainless steel shield with neoprene sleeve) over one pipe end.
3. Butt pipe ends together inside the coupling — the separator ring inside the neoprene centres the joint.
4. Tighten clamp bands alternately to specified torque: 60 in-lb (6.8 N·m) per CISPI 310. Over-torquing distorts the shield; under-torquing leaks.

5. Grooved Pipe Systems (Victaulic) — Skill 7.05

Grooved mechanical couplings — most commonly known by the brand name Victaulic — have become the standard for joining steel and copper pipe in mechanical rooms and fire protection systems. No welding, no threading, no open flame: just a groove, a gasket, and two coupling halves bolted together. On a church mechanical room with 20 connections and a tight schedule, grooved pipe saves days.

Grooving Methods

• Roll grooving: Cold-forms a groove by pressing a roller into the rotating pipe end. Preferred method — doesn’t remove material, maintains full wall thickness. Used on standard-wall and Schedule 10 pipe.
• Cut grooving: Machined groove cut into the pipe wall. Used on heavy-wall, lined, or coated pipe where roll grooving would damage the lining. Removes material, so minimum remaining wall thickness must be verified.

Assembly Procedure

1. Verify groove dimensions with a go/no-go gauge — groove depth, width, and distance from pipe end must be within manufacturer tolerances.
2. Lubricate the gasket with manufacturer-approved silicone lubricant. Never use petroleum-based products (degrades EPDM rubber).
3. Seat the gasket evenly over the pipe ends in the groove. Ensure no gasket lip is pinched or rolled under.
4. Place coupling housing halves over the gasket and hand-tighten nuts. Alternate tightening until housing pads are metal-to-metal — torque to manufacturer specification (typically 50–60 ft-lb for standard couplings).

6. Underground Plumbing (Below Slab) — Skill 7.06

Underground plumbing is the first piping installed on any church project and the last chance to get it right. Once the concrete slab is poured, those pipes are buried for the life of the building. Underslab sanitary, storm, and water piping must be precisely located, properly bedded, tested, and inspected before the concrete crew arrives. Coordination with formwork, rebar, and the surveyor is critical.

Key Considerations

• Invert elevations: Every underslab pipe must be installed to precise invert elevations per the plumbing drawings. A common choice is the Leica total station to verify inverts at every cleanout and change of direction. A 10 mm error at the building can become a 50 mm problem at the property line.
• Minimum slope: OBC Part 7 requires minimum slope of 1:50 (2%) for pipe 3″ and smaller, and 1:100 (1%) for pipe 4″ and larger. Always verify slope with a laser level or digital level — never eyeball it.
• Bedding: Pipe shall be bedded on 150 mm of compacted granular material (Granular “A” or pea gravel per specification). No rocks, frozen material, or debris in the bedding zone. Pipe must bear uniformly — point loads cause cracks and bellies.
• Backfill: Backfill in 200 mm lifts with mechanical compaction. Do not drop backfill directly onto pipe from height — dumping a bucket of gravel from a Bobcat onto PVC pipe will crack it.

7. Plumbing Fixture Installation — Skill 7.07

Fixture installation is where all the rough-in work comes together and the building actually starts to look like a building. Commercial fixtures in churches — wall-hung water closets, sensor-activated urinals, barrier-free lavatories, and drinking fountains — have tighter tolerances and more complex mounting requirements than residential fixtures. Every height, clearance, and grab bar location is governed by the OBC and AODA accessibility standards.

Barrier-Free (AODA) Requirements

• Water closet: Seat height 430–460 mm to top of seat. Minimum 1,500 mm clear floor space. Grab bars on side wall (840 mm long) and behind (610 mm long), mounted 840–920 mm above floor. Flush controls on the transfer side.
• Lavatory: Rim height maximum 865 mm. Knee clearance minimum 685 mm. Insulated supply and drain pipes to prevent contact burns for wheelchair users. Lever or sensor-activated faucets — no round knobs.
• Drinking fountain: Dual-height installation: accessible unit at maximum 915 mm spout height with clear floor space, plus standard-height unit. Both require bottle-filler functionality on church projects.

8. Backflow Prevention — Skill 7.08

Backflow prevention protects the municipal water supply from contamination by preventing reverse flow from a building’s plumbing system back into the public water main. Ontario municipalities and the OBC require backflow prevention devices on all commercial water services — and churches, with their commercial kitchens, custodial systems, and baptistry pools, are classified as moderate-to-high hazard facilities.

Device Types

• DCVA (Double Check Valve Assembly): Two independently operating spring-loaded check valves in series. Used for moderate hazard applications — domestic water service to a church without chemical injection systems. CSA B64.5 certified.
• RPZ (Reduced Pressure Zone): Two check valves with a differential relief valve between them. Used for high-hazard applications — boiler connections, chemical feed systems, irrigation with fertilizer injection. If either check valve fails, the relief valve opens and dumps water to a drain rather than allowing contamination. CSA B64.4 certified.

9. Plumbing Rough-In (Above Grade) — Skill 7.22

Above-grade rough-in is the marathon of plumbing installation — running waste, vent, and supply piping through walls, floors, and ceilings during the framing phase. It’s where the plumber needs to work closely with framers, electricians, HVAC, and fire protection to share the limited space inside walls and above ceilings. On a church project with tall sanctuary walls, long fellowship hall runs, and complex washroom groups, coordination is everything.

DWV Rough-In Essentials

• Vent termination: Vent stacks must extend through the roof a minimum 150 mm above the roof surface per OBC Part 7, and shall not terminate within 900 mm of any openable window, door, or air intake. On church projects with complex rooflines, coordinate vent penetration locations with the roofing subtrade early.
• Trap arm length: The distance from the trap weir to the vent connection must not exceed the values in OBC Table 7.2.5.3. (e.g., 1½″ trap arm — max 1,500 mm; 3″ trap arm — max 3,600 mm). Exceeding these distances invites siphonage and trap seal loss.
• Fire-stopping: All pipe penetrations through fire-rated assemblies must be fire-stopped with ULC-listed assemblies. This is not optional. The firestop system (brand, listing number) must match the specific penetration type — plastic pipe through concrete is a different system than copper through drywall.
• Support spacing: Horizontal copper — every 1.8 m for ½″ to 1″, every 3.0 m for 1¼″ and larger. ABS — every 1.2 m horizontal, every 1.8 m vertical. Cast iron — every 1.5 m horizontal, at every joint plus base of every stack.

10. Pressure Testing — Skill 7.23

Pressure testing is the moment of truth. Every joint you’ve soldered, threaded, glued, and coupled gets put to the test — literally. OBC Part 7 requires testing of all plumbing systems before concealment, and TSSA requires separate testing of gas systems. A failed pressure test means finding and fixing every leak before the walls close up. A passed test means you can sleep at night.

DWV Testing

• Water test: Fill the DWV system with water to the highest vent stack opening. Maintain a minimum 3 m (10 ft) head of water for 15 minutes with no drop. Plug all openings with test balls or expansion plugs. OBC Part 7 requirement.
• Air test (alternative): Pressurize DWV system to 35 kPa (5 psi) gauge pressure. Hold for 15 minutes with no pressure drop. Air testing is faster but less reliable for finding small leaks — use soap solution on all joints.

Domestic Water Testing

• Hydrostatic test: Pressurize to 1.5 times the working pressure or 100 psi, whichever is greater. Hold for 2 hours minimum with no pressure drop. Use a calibrated test gauge readable to 1 psi increments.
• Temperature compensation: If testing on a cold day, allow the water to stabilize to ambient temperature before starting the hold period. Cold water in warm pipes will cause apparent pressure rise; warm water in cold pipes will show apparent pressure drop. Neither is a leak — but the inspector wants a flat line.

Gas Piping Testing

• CSA B149.1 requirements: New gas piping must be tested at 15 psig (approximately 100 kPa) for a minimum 15-minute hold with no pressure drop, using air or inert gas (never test gas lines with water). Use a manometer or calibrated gauge readable to 0.1 psig.
• Leak detection: After initial pressure test passes, purge gas lines per CSA B149.1 requirements and check all joints with an approved leak detection solution or combustible gas detector. Document purge volumes and ensure adequate ventilation during purging.

11. Church-Specific Plumbing — Skills 7.07 & 7.22 Applications

Church buildings have unique plumbing requirements that you won’t find in a typical office or retail project. Baptistry pools require dedicated plumbing and heating systems. Fellowship hall kitchens need commercial-grade waste and grease management. Multiple washroom groups serving hundreds of people at once demand properly sized distribution. And every lobby needs accessible drinking fountains for a congregation that includes everyone from toddlers to seniors.

Baptistry Pool Plumbing

• Supply: Dedicated hot and cold supply with thermostatic mixing valve to maintain 32–36 °C water temperature. Size supply for fill time — a 3,000-litre baptistry should fill in under 2 hours using a ¾″ supply minimum.
• Circulation: Recirculation pump, filter, and heater system similar to a small pool. Chemical treatment (chlorine/bromine) or UV disinfection per local health authority requirements. The recirculation system keeps the water safe between baptism events.
• Drainage: Indirect drain connection to the sanitary system with an air gap — never a direct connection. Backflow prevention on the fill line is mandatory. Include a floor drain adjacent to the baptistry for overflow and splash management.
• Access: Design mechanical components (pump, heater, filter) for easy access — these will need regular maintenance. A dedicated mechanical closet adjacent to the baptistry is ideal.

Commercial Kitchen (Fellowship Hall)

• Grease interceptor: Required by OBC and municipal sewer use by-law for all commercial kitchen waste. Size per fixture unit count and local authority requirements. Interior point-of-use grease traps under three-compartment sinks, plus an exterior grease interceptor for the kitchen waste line.
• Hot water demand: Fellowship hall kitchens serving 200+ people need significant hot water capacity. Size the water heater for peak demand including dishwasher (82 °C), three-compartment sink, hand sinks, and pre-rinse spray. A dedicated kitchen water heater is often more practical than oversizing the building’s main system.
• Indirect waste connections: Walk-in cooler condensate drains, ice machine drains, and dishwasher drains shall connect to the sanitary system through indirect waste receptors (floor sinks) with air gaps per OBC Part 7. No direct connections from food equipment to the drainage system.

Multiple Washroom Groups

• Fixture count: OBC 3.7 determines minimum fixture counts based on occupant load. A 500-seat sanctuary with a 200-person fellowship hall requires substantially more fixtures than a typical office. Calculate occupant loads per room, not just total building area.
• Simultaneous demand: Unlike an office where washroom use is distributed throughout the day, church washrooms experience peak demand at intermission, between services, and after events. Size distribution piping for simultaneous use of 75% of fixtures — not the standard 50% diversity factor used in offices.
• Water hammer arrestors: With dozens of flushometer valves operating simultaneously, water hammer is a real concern. Install water hammer arrestors (CSA B125.4) at every flushometer valve supply and at the ends of branch supply lines. Nobody wants the walls vibrating during the sermon.

Lobby Drinking Fountains

• Dual-height with bottle fillers: Every HCMI church lobby includes dual-height drinking fountains with integrated bottle-filling stations. The lower unit meets AODA barrier-free requirements; the upper unit serves standing users. Bottle fillers are the most-used feature in any modern church building.
• Drainage: Floor drain within 600 mm of the fountain for overflow and cleaning. Indirect waste connection from the fountain basin to the drain.
• Supply filtration: In-line carbon filter on the supply to drinking fountains for taste and odour improvement. Filter housing with isolation valve for easy cartridge replacement by church maintenance staff.