IPC
Standard
International Plumbing Code
Application area
US plumbing design
Project relevance
Fixture unit tables, pipe sizing and venting requirements for US jurisdiction projects.
Public health engineering
Plumbing and public health engineering for multi-storey buildings
Cold and hot water distribution, drainage, venting and storm systems designed for hydraulic performance, maintenance access and regulatory compliance.
Service scope
Plumbing engineering at SEINZEN addresses the full public health scope from incoming water service through cold and hot water distribution, circulation, drainage, venting and storm management. Design begins with fixture unit analysis, peak demand estimation and pressure zone planning for multi-storey buildings.
Sanitary drainage systems are sized for peak discharge with venting designed to maintain trap seals and prevent siphonage across all occupancy types. Grease interceptors, trade waste pre-treatment and backflow prevention are integrated where kitchen, laboratory or industrial discharges require specialised treatment.
Pipe routing is coordinated through riser shafts and ceiling zones in Revit MEP models with hydraulic calculations, isometric drawings and equipment schedules issued at defined milestones. Material selection considers water quality, temperature, pressure and maintenance requirements.
Construction support includes submittal review, pressure testing oversight and coordination with structural, architectural and fire protection disciplines through installation and commissioning.
Key engineering capabilities
Domestic water distribution
Cold and hot water risers, branch piping and pressure reducing stations sized for peak demand and minimum pressure at fixtures.
Hot water generation and circulation
Calorifier, heat pump and instantaneous heater selection with return circulation pumps sized for temperature maintenance and energy efficiency.
Sanitary drainage design
Soil, waste and vent systems sized per applicable codes with stack venting, relief venting and trap seal protection.
Stormwater management
Roof and surface drainage with siphonic or gravity systems, attenuation and connection to municipal or on-site disposal.
Fixture unit analysis
Peak flow estimation using recognised methods with diversity applied per occupancy type and operating schedule.
Grease and trade waste
Interceptor sizing, kitchen waste routing and pre-treatment requirements for food service and laboratory discharges.
Backflow prevention
Device selection and location for cross-connection control per water authority and applicable plumbing codes.
Medical and process piping
Specialised piping for healthcare, laboratory and industrial process requirements coordinated with equipment suppliers.
Hydraulic calculation and modelling
Pipe sizing, pressure loss analysis and surge assessment for complex distribution networks.
Design and delivery methodology
- 01
Demand assessment
Fixture schedules, occupancy data and water authority requirements reviewed to establish design flows and pressure criteria.
- 02
Riser and zone strategy
Vertical routing, pressure zones and plant room locations defined with architectural and structural coordination.
- 03
Schematic design
System diagrams, preliminary pipe sizing and equipment selections issued for design team review.
- 04
Detailed design
Hydraulic calculations, isometric drawings, Revit models and specifications prepared to construction standard.
- 05
Coordination and issue
Federated model coordination and drawing issue with calculation reports for tender.
- 06
Testing and commissioning
Pressure testing, flushing procedures and flow verification support through handover.
Technical design criteria
Peak demand estimation
Fixture unit methods and probability-based approaches applied per IPC, UPC, EN 806 or project-specific criteria.
Pressure zone design
Static and dynamic pressure limits at fixtures with PRV stations, break tanks and booster sets where building height exceeds code limits.
Hot water temperature control
Delivery temperature limits, mixing valve requirements and Legionella control strategies for stored and recirculated systems.
Drainage stack sizing
Discharge unit loading, stack capacity and branch connection limits per applicable drainage codes.
Vent system design
Individual, common and relief venting to protect trap seals with air admittance valve application where permitted.
Pipe material selection
Copper, stainless steel, CPVC, HDPE and cast iron selection based on water quality, temperature, pressure and application.
Siphonic roof drainage
Full-bore flow design, pipe sizing and vacuum breaker requirements for large roof areas.
Rainwater harvesting integration
Collection, storage, treatment and reuse systems coordinated with storm management and irrigation requirements.
Acoustic isolation
Pipe bracketing, flexible connections and routing strategies to meet noise criteria in sensitive occupancies.
Seismic and expansion provision
Expansion loops, flexible connectors and restraint design for risers in seismically active regions.
Engineering principles and calculation approaches
Q = K × √P
Variables
Q = flow rate (L/s); K = discharge coefficient; P = pressure at fixture (kPa)
Application
Individual fixture flow estimation for branch pipe sizing at design pressure.
Notes
Apply code-specific discharge coefficients; verify against manufacturer data for specialised fixtures.
DUF = Σ(FU × DF)
Variables
DUF = diversified fixture units; FU = fixture units; DF = diversity factor
Application
Peak demand estimation for water supply riser and branch sizing.
Notes
Diversity factors vary by occupancy type and applicable plumbing code edition.
ΔP = f × (L/D) × (ρv²/2)
Variables
ΔP = pressure drop (Pa); f = friction factor; L = pipe length (m); D = internal diameter (m); ρ = fluid density; v = velocity (m/s)
Application
Pipe friction loss calculation for pump head and pressure zone verification.
Notes
Include fitting equivalent lengths; limit velocity per code and noise criteria.
Q = A × v
Variables
Q = volumetric flow rate (m³/s); A = pipe cross-sectional area (m²); v = flow velocity (m/s)
Application
Drainage pipe sizing verification against minimum scouring velocity and maximum capacity.
Notes
Apply partial fill factors for gravity drainage; verify slope requirements per code.
V = Q × t
Variables
V = storage volume (L); Q = peak demand flow (L/s); t = storage duration (s)
Application
Break tank and storage vessel sizing for pressure management and emergency supply.
Notes
Include safety margins and refill rate requirements per water authority regulations.
Final design values must be determined using project-specific inputs, applicable standards, manufacturer data and engineering judgement.
BIM, Revit and integrated design
Plumbing systems are modelled in Revit MEP with pipework, fittings, equipment and insulation represented at defined LOD for coordination and quantity extraction.
Pipe system classifications, sizes and slopes are defined in model parameters with schedule views linked to hydraulic calculation outputs.
Riser diagrams are cross-referenced to model elements with consistent tagging across isometric drawings and floor plans.
Federated coordination resolves routing conflicts with structural beams, HVAC ductwork and electrical cable trays before construction issue.
International standards and codes
UPC
Standard
Uniform Plumbing Code
Application area
US plumbing design
Project relevance
Alternative US code with fixture unit and drainage sizing provisions.
EN 806
Standard
Specifications for Installations Inside Buildings Conveying Water for Human Consumption
Application area
European water supply
Project relevance
Design flow rates, pipe sizing and material requirements for potable water systems.
EN 12056
Standard
Gravity Drainage Systems Inside Buildings
Application area
European drainage
Project relevance
Discharge unit loading, stack sizing and venting for sanitary drainage systems.
ASME B31.9
Standard
Building Services Piping
Application area
Process and building piping
Project relevance
Design requirements for non-potable and process piping systems.
BS EN 806
Standard
Drinking Water Installations
Application area
UK water supply
Project relevance
UK-adopted European standard for potable water distribution design.
CIBSE Guide G
Standard
Public Health Engineering
Application area
UK public health design
Project relevance
Design guidance for water supply, drainage and sanitary installations.
WHO Guidelines
Standard
Guidelines for Drinking-Water Quality
Application area
Water quality
Project relevance
Reference for water treatment and quality requirements in healthcare and sensitive occupancies.
ASPE
Standard
Plumbing Engineering Design Handbook
Application area
Plumbing engineering reference
Project relevance
Design methods, fixture data and calculation procedures for plumbing systems.
NFPA 99
Standard
Health Care Facilities Code
Application area
Healthcare plumbing
Project relevance
Medical gas coordination and specialised plumbing requirements for healthcare buildings.
BS 6700
Standard
Design, Installation, Testing and Maintenance of Services Supplying Water for Domestic Use
Application area
UK domestic water
Project relevance
Historical UK reference; superseded in part by EN 806 but retained for existing installations.
Local Water Authority Regulations
Standard
Municipal Connection Requirements
Application area
Utility connection
Project relevance
Backflow prevention, meter sizing and connection approval requirements per jurisdiction.
| Code | Standard | Application area | Project relevance |
|---|---|---|---|
| IPC | International Plumbing Code | US plumbing design | Fixture unit tables, pipe sizing and venting requirements for US jurisdiction projects. |
| UPC | Uniform Plumbing Code | US plumbing design | Alternative US code with fixture unit and drainage sizing provisions. |
| EN 806 | Specifications for Installations Inside Buildings Conveying Water for Human Consumption | European water supply | Design flow rates, pipe sizing and material requirements for potable water systems. |
| EN 12056 | Gravity Drainage Systems Inside Buildings | European drainage | Discharge unit loading, stack sizing and venting for sanitary drainage systems. |
| ASME B31.9 | Building Services Piping | Process and building piping | Design requirements for non-potable and process piping systems. |
| BS EN 806 | Drinking Water Installations | UK water supply | UK-adopted European standard for potable water distribution design. |
| CIBSE Guide G | Public Health Engineering | UK public health design | Design guidance for water supply, drainage and sanitary installations. |
| WHO Guidelines | Guidelines for Drinking-Water Quality | Water quality | Reference for water treatment and quality requirements in healthcare and sensitive occupancies. |
| ASPE | Plumbing Engineering Design Handbook | Plumbing engineering reference | Design methods, fixture data and calculation procedures for plumbing systems. |
| NFPA 99 | Health Care Facilities Code | Healthcare plumbing | Medical gas coordination and specialised plumbing requirements for healthcare buildings. |
| BS 6700 | Design, Installation, Testing and Maintenance of Services Supplying Water for Domestic Use | UK domestic water | Historical UK reference; superseded in part by EN 806 but retained for existing installations. |
| Local Water Authority Regulations | Municipal Connection Requirements | Utility connection | Backflow prevention, meter sizing and connection approval requirements per jurisdiction. |
Applicable standards depend on the project location, building use, authority having jurisdiction, employer requirements and contract documents. The current adopted edition must be confirmed at the beginning of each project.
Project deliverables and documentation
Fixture schedule and demand calculation
Fixture unit analysis with peak flow estimates and diversity factors documented.
Water supply schematic drawings
Cold, hot and circulation system diagrams with riser and branch routing.
Drainage and vent isometric drawings
Soil, waste and vent systems with stack connections and trap details.
Hydraulic calculation reports
Pipe sizing, pressure loss and pump head calculations for water supply systems.
Equipment schedules
Pumps, calorifiers, PRV stations, interceptors and storage vessel schedules.
Revit MEP plumbing models
Coordinated plumbing models with pipework, fittings and equipment at defined LOD.
Storm drainage design
Roof and surface drainage calculations with pipe sizing and attenuation provisions.
Performance specifications
Technical specifications for pipework, valves, equipment and installation prepared for tender.
Riser diagrams
Vertical routing diagrams for water supply and drainage stacks coordinated with structure.
Grease and trade waste assessment
Interceptor sizing and discharge requirements for kitchen and laboratory waste streams.
Testing and flushing procedures
Pressure test, disinfection and commissioning requirements for water supply systems.
O&M documentation requirements
Valve schedules, isolation points and maintenance access requirements for handover.
Quality control and verification
Fixture schedules cross-checked against architectural layouts before hydraulic calculations commence.
Pipe sizing independently verified against code limits for velocity, pressure drop and drainage capacity.
Venting design reviewed for trap seal protection across all branch connections and stack conditions.
Model routing validated through federated clash detection with structural and MEP disciplines.
Material selections confirmed against water quality data and temperature requirements.
Submittal deviations tracked and resolved before installation approval.
Applicable project types
Multi-storey residential towers with centralised hot water and metered cold water distribution.
Hotels and hospitality projects with high fixture density and kitchen waste requirements.
Healthcare facilities with specialised drainage, temperature control and medical gas coordination.
Commercial office buildings with tenant toilet cores and common area sanitary facilities.
Laboratory and research facilities with acid waste, trade waste and emergency shower systems.
Mixed-use developments with retail food service and residential plumbing segregation.
Frequently asked questions
How are pressure zones determined for high-rise buildings?
Pressure zones are established based on static head limits at fixtures per applicable code, typically 45–50 m maximum. PRV stations, break tanks or intermediate booster sets are introduced at floor levels where building height exceeds single-zone capability.
What approach is used for Legionella control in hot water systems?
Stored hot water temperature, circulation return temperature and dead leg minimisation are addressed in design. Risk assessment and monitoring protocols are coordinated with operational teams; supplementary treatment may be specified for healthcare projects.
How is kitchen grease waste managed in commercial buildings?
Grease interceptor sizing follows fixture discharge and local authority requirements. Routing, venting and maintenance access are coordinated with kitchen layouts and drainage stacks before detailed design issue.
Can siphonic drainage be used on large roof areas?
Siphonic systems are appropriate for large flat roofs where full-bore flow design reduces pipe sizes and routing complexity. Design follows manufacturer-specific hydraulic requirements with vacuum breaker and overflow provisions.
How is plumbing coordinated with structural and architectural design?
Riser locations and ceiling zone allocations are agreed at schematic stage. Revit MEP models are federated with architectural and structural models with clash detection resolving routing conflicts before construction issue.
Discuss plumbing engineering scope
Contact our public health engineering team to review water supply strategy, drainage design or hydraulic calculations for your building.