SWR Type A vs Type B for Building Drainage
SWR Type A vs Type B and Which Pipe Is Used for Rainwater, Vents, Soil and Waste
In the Finolex SWR range, Type A is used for rainwater and vent applications, while Type B is used for soil and waste discharge. Both belong to non-pressure drainage plumbing, so the choice is based on what the line carries and how the drainage system is designed, not on pressure-pipe logic.
Finolex SWR pipes conform to IS 13592 and are used in residential, commercial and institutional drainage systems. The range also includes different jointing arrangements, so Type A or Type B should not be confused with Selfit or integrated-ring jointing.
First identify what the pipe will carry
A building may have several drainage routes that look similar on a drawing but perform different jobs. A toilet soil line carries a different discharge from a terrace rainwater downpipe. A vent line serves another function again. The material schedule should identify each route clearly before pipe is ordered.
If a buyer simply asks for "drainage pipe," the dealer may need more information. State whether the line is for soil discharge, bathroom or kitchen waste, rainwater or venting. This one clarification narrows the correct product category much faster.
What Type A means in an SWR system
Type A SWR pipe is associated with rainwater and vent applications. Examples can include vertical rainwater lines from terraces or roof areas and vent lines provided as part of the drainage design.
The actual diameter and fitting layout still depend on the building design, rainfall load, number of fixtures or venting requirement. Type A describes the application category; it does not replace sizing calculations.
What Type B means in an SWR system
Type B SWR pipe is used for soil and waste discharge. In a typical building this may include lines carrying discharge from toilets, bathrooms, wash areas or other sanitary fixtures as specified by the plumbing design.
Because these lines form part of a gravity drainage system, slope, fitting layout, access for cleaning and correct connection to the next drainage stage are important. The pipe type should be selected together with the full fitting schedule.
Do not confuse pipe type with jointing method
Finolex SWR products include Selfit and integrated-ring options. Selfit joints use the specified plumbing solvent cement, while the integrated-ring system uses a pre-fitted ring and lubricant for insertion. These are jointing choices within the broader SWR system.
A buyer can therefore have two separate questions. Is this line Type A or Type B? Which jointing system is specified? Keeping those questions separate reduces incorrect substitutions at site.
Plan fittings around maintenance access
Drainage performance depends on more than straight pipe lengths. Bends, branches, traps, access fittings, reducers and connections to stacks or underground lines all need to match the approved layout. A pipe order without the fitting schedule can leave installers improvising on site.
Ask the plumber where cleaning access will be required and which fittings are needed at direction changes. The dealer can then check stock against an actual list rather than estimating from the number of pipe lengths.
What to tell the dealer before purchase
Bring the drawing or plumber-prepared material list if available. State the application for each pipe run, the nominal size, Type A or Type B, jointing preference and fitting quantities. For repair work, take a clear photo of the existing pipe markings and the fitting that needs replacement.
Use the SWR Pipes & Fittings product page to review the official range. If local availability needs to be confirmed, the Find a Dealer page can help identify a nearby authorised Finolex outlet.
Frequently asked questions
Is Type A stronger than Type B?
Type A and Type B primarily distinguish intended SWR applications. Type A is for rainwater and vents, while Type B is for soil and waste discharge. The design should specify the correct type and size.
Are SWR pipes pressure pipes?
Finolex SWR pipes are intended for non-pressure drainage applications.
Is Ringfit the same as Type B?
No. Ringfit or Selfit describes how sections are joined. Type A or Type B describes the SWR application category.
