The Architect's Guide to Hydraulic & Wet Fire Services Coordination

Hydraulic and fire services must be coordinated early. Poor coordination can result in undersized risers, insufficient ceiling space, drainage clashes, non-compliant wet areas, and fire equipment being added as an afterthought. This guide highlights the key coordination points architects should check before issuing drawings.

1. When Are Hydraulic Engineers Engaged?

Timing: Engaged during Concept or Schematic Design to establish risers, shafts, drainage strategy and fire services. Early coordination prevents costly redesigns.

Building Classes: All building classes require hydraulic services. Larger buildings typically include fire hydrants, hose reels, sprinklers, trade waste and specialist systems.

2. Key Coordination Items

A. Risers& Shafts

Hydraulic engineers determine the services required (water, sewer, stormwater, fire and trade waste), while architects provide adequate space.

Check that:

• All risers and shafts are shown on architectural plans.

• Shaft sizes allow for pipes, vents, insulation and maintenance access.

• Access panels are provided for valves and equipment.

• Risers align floor-to-floor and avoid clashes with doors, windows and structure.

B. Wet Areas & Slab Set-downs

Architects determine slab set-downs, but they must accommodate waterproofing, finishes and plumbing falls.

Check that:

• Set-down depth takes into account the termination height, floor finish thickness, and falls to the external slab.

• Floor wastes and falls are shown on the concrete set-down plan.

• Floor waste locations work with the hydraulic system (traditional/siphonic/charged).

• Linear drains and floor waste match the finishes schedule.

C. Sanitary Drainage

Drainage pipes require falls, traps and venting, all of which affect ceiling space and wall construction.

Check that:

• Drainage falls fit within ceiling or slab depths.

• Vent pipes are included in shaft sizing.

• P-traps and S-traps suit the wall or floor construction.

• Air Admittance Valves (AAVs) remain accessible for maintenance.

D. Stormwater & Roof Drainage

Coordinate roof drainage, downpipes and overflow systems early.

Check that:

• Downpipes align with roof and façade layouts.

• Overflow paths discharge visibly outside the building.

• Drainage layouts are finalised early, as they cannot easily be relocated.

E. Ceiling Coordination

Hydraulic, fire, mechanical, electrical and structural services all compete for ceiling space.

Check that:

• Services clear structural beams and slab thickenings.

• Required ceiling heights are maintained.

• Sprinkler heads align with the reflected ceiling plan.

F. Fixtures & Appliances

Architectural layouts determine fixture locations, but services must support them.

Coordinate:

• Accessible fixtures with AS 1428.1.

• Concealed cistern wall depths.

• Water and drainage connections for appliances.

• Maintenance access to all concealed equipment.

G. Fire Services

Fire equipment should be integrated into the design, not added later.

Coordinate:

• Recessed fire extinguisher and hose reel cabinets.

• Fire booster locations.

• Sprinkler layouts and ceiling coordination.

• Clearance between sprinklers and ceiling fans.

3. Architectural Coordination Checklist

Before issuing drawings, confirm:

• Hydraulic risers and shafts match architectural plans.

• Wet-area set-downs, floor wastes and drainage falls are coordinated.

• Under-slab drainage avoids structural footings.

• Ceiling services fit within available space.

• Stormwater and sewer connections align with site infrastructure.

• Fire equipment locations are coordinated.

• Hydraulic fixtures and fire services are included in the specification.

4. Common Coordination Pitfalls

• Undersized Risers: Forgetting vents, insulation or maintenance access results in larger shafts during construction.

• Drainage Fall Clashes: Pipe falls reduce ceiling height and clash with structure if not coordinated early.

• Poor Stormwater Coordination: Hidden overflows can lead to water damage.

• Inaccessible Pipework: Cast-in services and concealed cisterns without access become expensive to repair.

• Fire Equipment Added Late: Surface-mounted extinguishers and hose reels compromise aesthetics and compliance.

• Using Outdated Drawings: Working from superseded consultant drawings causes costly site clashes.