Case Study: Piping System failures – cPVC in Premium residential society
Background
• A high rise, premium Apartment Block on Noida Expressway.
• 70,000 sqm area, Project cost of Rs 750 Crores
• The Society has 12 storey buildings, 17 towers and 4 flats/ floor. Total of about 600 flats.
• Ultramodern, 3&4 bedroom apartments and Penthouses with world class specifications
• Prime features - High-tech security, dedicated parking, Modular Kitchen with piped gas supply, Wooden Flooring, Ultra Modern Toilets, In-home Maintenance services etc. Moreover there is an in-house club with five-star offerings.
Current Status
• Flats being Handed over to the clients. Residents living in the complex for about 1 year now.
• Piping of CPVC (both external as well as in the toilets)
• External cPVC pipes running through shafts.
• Reputed cPVC manufacturer has supplied the piping system.
Issues informed to the plumbing experts
• All Flats are having problem of water seepage.
• The main pipes are getting cracked, joints leaking and the maintenance offices being flooded with complaints to rectify the problems everyday.
• The initial savings in piping material has cost the builder huge amount of money in repair and loss of reputation
Problems identified by the Project Manager
• Pipes getting deformed
– Adequate supports not provided.
• Pipes are brittle, even a small stone lying on some slab when it falls leads to pipe breakage
• The joints are leaking
– In main pipeline in all the towers
– In the toilets
– Each and every of the 600 flats have complained.
• High flow rate (no PRV)
• Joints are not durable
• When Taps/ Fittings are tightened, the pipe cracks in the toilet
• Even the repair is not reliable
• Management feeling helpless and groping in dark for solutions
Technical Analysis
• CPVC has highest thermal expansion coeff.
– For 50ºC change in temp, the 30m cPVC pipe expands by 15cm
• cPVC is brittle and at low temperature, the thin walled system is extremely brittle. They may crack even on dropping from height
• CPVC pipe and fittings are subject to cracking during earthquakes.
• Permitted flow rate is 2m/sec.
• Loud noise can be heard when water flows in some cases.
• Not all the technical issues are discussed with the Builders/ Management and decisions are made on some sales pitch
Possible Reasons for the cPVC pipe Failure
1. Thermal Expansion
• The Pipes would have been installed in Summers when the temperature was nearing 45C
• In winters (temp nearing zero C), the pipes get shrunk, leading to buildup of the stresses.
• Design to address the Expansion issue was not done.
2. Joining
• If there is too much glue applied it can actually dissolve the pipe and cause a failure.
• The jointing by solution can’t withstand these stresses and start leaking.
• Repairs may temporarily provide relief but in the summers, reverse situation will happen.
3. Inadequate Supports
• The cPVC Pipes need support at every 4’ otherwise it leads to problems
4. Brittle Material
• cPVC is a brittle material. It is not suitable for external usage in extreme weather conditions
5. Connectors
• Need to use Brass connectors for threaded fittings which is expensive
6. Future Problems
• High flow rate will soon aggravate the problem as the wear of pipe over next few years
7. Freezing Waters
• The freezing water temperature will make the pipes brittle. Need to use it carefully.
8. Ultravoilet Rays
• The cPVC pipes need to be protected from direct sunlight / UV Exposure.
9. Ageing
• As cPVC pipes age, the pipes become brittle and must be protected from physical shocks to avoid failures
10. Toxic
• When cPVC is burned (eg house fire), it emits a deadly toxic fume.
11. Installations
• Pipes if not installed properly are prone to Environment Stress Cracking
12. Damage from Rodents
• For reasons known only to rodents CPVC is highly subject to damage from rats, mice, squirrels and Opossums and may not be a good choice of materials for running under a structure with a crawl space or raised foundation, especially in rural areas
References:
· This is based on the analysis of the site and actual discussions with the management of the builder.
· The reference data is taken from various sources on the net and the websites of the cPVC pipe manufacturers.
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