Drainage pipe is the part of a building nobody sees and everybody depends on. It is buried in slabs, hidden in shafts and cast into walls, and it works for decades only if it was made well and installed well. When it fails, the symptoms are damp patches, smells, blocked lines and leaks, and the cure is breaking tiles, chasing walls and often disturbing the flats above and below.
Poor SWR pipe is common because it looks fine. A thin-walled pipe in the right colour and the right diameter passes a quick glance. This guide gives you practical checks you can run at the shop or on site: how to read the marking, how to verify the BIS licence, how to judge wall thickness for Type A and Type B pipe, how to check ring and socket fit, how to compare weight, what documents to ask for, and how to test a line after installation. It follows the same trust-building approach as our guides on identifying fake conduit pipe and checking CPVC pipe quality, applied to drainage.
Know the standard: IS 13592
SWR pipes in India are made to IS 13592, the Indian Standard for unplasticized PVC pipes for soil and waste discharge systems inside buildings, and Trity's SWR pipes comply with IS 13592 (Parts 1 and 2). These are non-pressure pipes, so they are tested and rated differently from water supply pipe, and the two must never be swapped. Our guide on SWR pipes vs PVC pipes explains why.
The standard covers dimensions, wall thickness, material and testing, and it defines the pipe types you see in the market. Trity's Ringfit range is made in Type A, for ventilation and rainwater, and Type B, for soil and waste discharge. The type decides the wall thickness, so you must know which one you are holding.
Check 1: Read the marking on the pipe
A genuine pipe carries printed information along its length. Look for:
- The standard, IS 13592
- Nominal size
- Pipe type, A or B, where applicable
- The manufacturer's name or trademark
- A batch or production code
- The ISI mark with a BIS licence number
Missing marking, marking that rubs off with a thumb, or a carton that says "ISI quality" while the pipe itself has no licence number should make you careful. A manufacturer that stands behind its product prints clear, permanent information on the pipe, not just on the packing.
Check 2: Verify the BIS licence number
A printed mark costs nothing. A valid licence does. Take the licence number from the pipe or the supplier and check it on the BIS database.
- The number exists and is valid
- It is issued for the relevant product standard, not an unrelated product
- It is current, not suspended or cancelled
- The manufacturer named on the licence matches the name on the pipe
Our certifications page shows Trity's credentials, including ISO 9001:2015, and you are free to check any licence number yourself.
Check 3: Measure wall thickness
Wall thickness is where cheap pipe saves money, because less compound means lower cost. Measure it.
- Cut a clean cross-section from an end of the pipe, or use a pipe cut on site
- Measure the wall at four or more points around the circumference with a vernier caliper
- Compare it with the minimum wall thickness for that diameter and type in IS 13592
- Look at consistency. A wall that is much thicker on one side than the other points to poor extrusion control, even if the average passes
- Check more than one length from the delivery, and from more than one bundle
Type B pipe has a thicker wall than Type A of the same diameter, so a Type A pipe supplied as Type B is a common substitution. If a supplier cannot tell you the type, or the measured wall does not match the type marked, stop and ask.
Check 4: Weigh a length
For a given diameter and type, pipe within the standard has a predictable weight per metre. Weigh a measured length and compare it with the manufacturer's published figure. A pipe that is clearly lighter than the figure usually has a thinner wall or a poorer compound. Ask your supplier for the weight per metre for the diameters and types you are buying, and keep a simple reference at your store so incoming deliveries can be checked in a minute.
Check 5: Look at colour, surface and finish
Good SWR pipe has an even colour along its length, a smooth inner and outer surface and a clean cut end with a dense, uniform cross-section. Warning signs include streaks or patches of different colour, dark specks, a rough or pitted bore, bubbles or voids in the cut face and a chalky residue that comes off when you rub the surface. A rough bore also catches solids and invites blockages. No single sign is conclusive, but several together point to mixed or recycled material.
Check 6: Inspect the socket and the ring groove
The joint decides whether a drainage system leaks, so check it before you buy in quantity.
For Ringfit pipes
- The socket should have a clean, smoothly formed groove with no flash or burrs
- The rubber ring should sit snugly in the groove, not loose and not twisted
- The ring should be a proper elastomeric ring, flexible and free from cracks
- The spigot end of the pipe should be cut square and chamfered, so that it enters without cutting the ring
- Dry fit a pipe into a socket: it should slide in with a little lubricant and stop firmly, with no wobble
For Selfit pipes
- The socket should be smooth inside, with a consistent depth and diameter
- A dry fit should go in part way and grip, so that solvent cement can complete the joint
- A test joint made with the correct solvent cement should not separate by hand after it cures
Our guide on Ringfit vs Selfit SWR pipes explains how each joint works, and our SWR installation guide covers jointing practice.
Check 7: Match the fittings
Fittings must match the pipe. Bends, tees, junctions, reducers, traps and access fittings should come from the same manufacturer as the pipe, or at least be dimensionally matched, because mixed tolerances cause loose or over-tight joints. Check that the fittings carry markings, have smooth bores and show consistent wall thickness. A fitting with a thin wall at the bend or an uneven socket is a weak point.
Check 8: UV exposure for outdoor pipes
Rainwater downpipes and exposed vents see sunlight. Our product page describes Trity's SWR pipes as UV stabilised for outdoor exposure. If you are buying pipe for exposed runs, ask the supplier to confirm UV stabilisation in writing, since ordinary pipe can chalk and turn brittle in sun.
Check 9: Ask for the documents
A reliable manufacturer provides documents without fuss. Ask for:
- The BIS licence details
- The ISO 9001:2015 certificate
- IS 13592 test reports for the product and batch
- A datasheet with diameters, types and dimensions
- A batch code that matches your delivery
Trity provides certification documents and test reports on request for tenders and procurement files, and sample lengths can be discussed for evaluation on larger orders.
Price and supplier red flags
- A rate far below other suppliers for the same diameter and type. Our guide on SWR pipe price explains why unusually low rates usually mean thin walls or poor compound.
- No type stated, or a supplier who cannot say whether pipe is Type A or Type B
- Marking missing or unreadable
- Reluctance to share a licence number or test reports
- Verbal quotes only, with no written validity
- Pipe sold per kilogram with no weight per metre, which makes thin walls easy to hide
- No batch information, which makes any later claim impossible to trace
Test the line after installation
Quality checks do not end at the shop. Before you conceal any drainage line, test it.
- Fill the line with water and watch the level over a reasonable time. A falling level points to a leak
- Check every joint visually while the line is full
- Check slopes and supports so that the line drains freely
- Record the test with the date and location
For taller buildings, our guide on SWR pipe sizing for multi-storey buildings explains stack sizing and venting, which also affect performance.
A quick checklist for the store
- Marking shows IS 13592, size, type, manufacturer and batch
- BIS licence number checked on the database
- Wall thickness measured and matched to the type
- Weight per metre matches the published figure
- Colour and surface even, bore smooth
- Rings and sockets fit without looseness
- Fittings matched to the pipe
- Documents and a written quotation received
Why plumbers and builders choose Trity SWR pipes
Trity Pipes manufactures SWR pipes and fittings in Ringfit and Selfit systems, from 40mm to 315mm, to IS 13592, with ISO 9001:2015 certification and quality checks at each stage of production. We offer matching fittings so that the whole drainage system can come from one manufacturer, and our team can help you choose type, joint system and sizes for your project. You are welcome to ask for documents, samples and a factory visit before you place a large order. See the full SWR pipes and fittings range.
Builders can ask for bulk and phased supply for multi-unit projects, and plumbing dealers can ask about stocking the range. If your project needs water supply as well, we make CPVC pipes and fittings and uPVC pressure pipes.
Frequently Asked Questions
How can I tell if SWR pipe is genuine?
Check the marking for IS 13592, size, type and batch, verify the BIS licence number, measure the wall thickness against the type, compare weight per metre, inspect the socket and ring, and ask for test reports. Several checks together are far more reliable than any one.
What is the difference between Type A and Type B SWR pipe?
Type A is used for ventilation and rainwater lines, and Type B for soil and waste discharge. Type B has a thicker wall, so supplying Type A where Type B is required is a common substitution to watch for.
How do I check the wall thickness of SWR pipe?
Cut a clean cross-section, measure the wall at four or more points with a vernier caliper, and compare with the minimum in IS 13592 for the diameter and type. Check more than one length from the delivery.
Can I use SWR pipe for water supply?
No. SWR pipes are non-pressure drainage pipes. Water supply needs pressure pipe such as CPVC or uPVC pressure pipe, rated for the working pressure.
Which documents should I ask an SWR supplier for?
The BIS licence details, ISO certificate, IS 13592 test reports for the batch, a datasheet with diameters and types, and a batch code that matches your delivery.
Can Trity Pipes provide test reports and samples for SWR pipes?
Yes. Contact our team with your requirement, and we will discuss certification documents, test reports and sample lengths for evaluation, along with a written quotation.
Want SWR pipe you can verify? Contact Trity Pipes on +91-9821030072 or +91-9319984755 for a quotation, documents and samples for ISO-certified SWR pipes and fittings from our Delhi NCR factory.