Fixture hydraulic load
Supported fixture classifications establish drainage fixture units. Verify private/public use and the specific fixture arrangement; water-supply fixture units are a different quantity.
Sanitary Drainage Design Software
Sanitary Drainage Design Software. Follow the Fixture Load Downstream.
Lay out gravity sanitary drainage over a PDF plan. Review fixture units, branch and stack pipe sizing, building-drain slope and fall in MEPFlow’s Sanitary Drainage module.
30 days free. Then $50 USD/month. No credit card required.
Sanitary sizing illustration · MEPFlow example project.
The connected workflow
Keep the design and the engineering together.
MEPFlow’s separate Drainage module connects a sanitary fixture layout with gravity pipe-sizing checks. It uses drainage fixture units and Canadian NPC 2020 reference tables, with distinct checks for branches, stacks and building drains. It does not reuse domestic-water demand or pump calculations.
- Place supported sanitary fixtures and connected downstream runs.
- Review branch, total-stack and busiest-storey fixture-unit loads.
- Apply nominal pipe sizing with slope-specific building-drain checks.
- Inspect pipe length, fall, invert elevations and sizing warnings.
Design scope: gravity sanitary pipe sizing. Venting, trap arms, cleanouts, stack offsets, pumped wastewater and storm drainage require separate design. Verify the adopted code edition and local amendments for your project.
01 / System layout
Design from the floor plan.
Use the Drainage module inside a project to apply a shared PDF drawing, place supported sanitary fixtures, connect directed branches/mains and add vertical floor stacks. Inspect fixture classifications, flow direction and node connections before sizing.
See how to get started02 / Calculations & sizing
From fixture layout to a reviewed gravity network
- 01
Place fixtures and connect
Apply the scaled drawing, choose supported sanitary fixture types and connect directed branches, mains and floor stacks.
- 02
Review load and fall
Inspect fixture units, connection direction, invert levels and design slopes. Follow the accumulated load downstream and check the busiest storey on a stack.
- 03
Apply sizing and inspect
Run Auto-size, review nominal diameters and warnings, and check any locked size overrides. Recheck the result after altering geometry or fixture demand.
Sanitary Drainage Checks
A single fixture-unit total cannot represent every part of a gravity drainage system. The module keeps these checks separate.
Branches and stacks
Branch capacity and stack capacity use different table checks. Stacks also need the maximum load entering from one storey, so total fixture units alone are insufficient.
Building drains and slope
Building-drain capacity depends on the applicable pipe size and selected slope. Review actual fall and inverts as well as the nominal sizing result.
Connections and overrides
The layout provides directed connections and vertical floor stacks. Locked pipe sizes remain visible for review, and invalid or incomplete network conditions generate warnings.
03 / Review your design
When the design changes
Connected fixture units and warnings update as the network changes. Apply Auto-size to choose supported nominal pipe sizes, or lock a deliberate size override for review. Inspect invert elevations, actual fall and design slope. Changed geometry or engineering inputs can make the previous sizing receipt stale.
Results and outputs
The module presents pipe-by-pipe fixture units, selected sizes, lengths, falls, slopes and warnings on screen. It covers gravity sanitary pipe sizing only. Venting, trap arms, cleanouts, stack offsets, pumped waste, stormwater and drainage report/drawing exports are not included in this advertised scope.
Built for your work
For sanitary drainage layout and preliminary sizing
Sanitary drainage sizing is more than totaling a fixture schedule. Branch load, total stack load, the busiest storey and building-drain slope are separate checks. A disconnected schedule can hide an incorrect downstream connection or a branch with insufficient fall.
- Plumbing designers checking Canadian gravity sanitary networks.
- Mechanical consultants reviewing fixture schedules and downstream loads.
- Contractors working through routing and fall with the design team.
- Engineers who will complete venting and jurisdiction-specific checks separately.
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A few more details
Your questions, answered.
Is sanitary drainage available in MEPFlow?
Yes. Sanitary Drainage is included alongside the other MEPFlow design modules. Its advertised scope is gravity sanitary layout and pipe sizing with fixture-unit, slope, fall and stack-load review. Review the results and complete checks outside that scope separately.
Does the module design stormwater drainage?
No. Rainfall intensity, roof catchment areas, stormwater sizing and storm drainage networks are outside the current advertised module scope.
Does it size vents and trap arms?
No. A sanitary pipe-size result does not complete venting, trap-arm, cleanout or fitting design. Those items and local amendments need a separate review.
What Canadian plumbing code is the sizing based on?
The module uses NPC 2020 reference fixture-load and sanitary capacity tables. This is a stated calculation basis, not a certification of the complete design. Confirm the code edition adopted in your province and the local authority requirements.
How are drainage fixture units different from water-supply fixture units?
Drainage fixture units describe hydraulic load for the sanitary system. Water-supply fixture units are used for demand in the pressurized supply system. Their tables and calculations are different and should not be substituted.
Can I check a sanitary pipe size for free?
Yes. The public Canadian sanitary drain calculator and worked guide are available without an account. Use the application when you want the connected fixture layout and network review.
Does drainage include pump duty or a report export?
Pumped waste and drainage report/drawing exports are not part of this module’s published scope. Review the available pipe-by-pipe results and warnings on screen.
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Automatic MEP sizing
The spreadsheet chain
ends here.
Loads. Airflow. Ductwork. Pipework. Hydronics. Drainage. 3D. One connected engineering workflow.