| Designers, contractors and building owners face a | | | | volatility of global copper index pricing. |
| myriad of factors in selecting the appropriate drain, | | | | Installation Costs - CI is heavy to transport and handle |
| waste and vent piping for new construction or retrofits. | | | | on the job but has a relatively simple assembly method |
| Issues such as flow capacity, longevity, joint tightness, | | | | when ready to install. Copper is lighter weight and easy |
| certifications, corrosion resistance, capital cost, | | | | to cut but time consuming for soldered joints, especially |
| installation cost, environmental effects, noise generation | | | | for smaller lines where many fittings are required. PVC |
| and thermal effects all warrant investigation. | | | | is both light weight to transport and handle and quick |
| The three main products used today in Canada for | | | | and easy for joining due to the straight forward |
| commercial construction are cast iron (CI), copper and | | | | solvent welding process. In sizes 8 inch and larger, |
| Polyvinyl Chloride (PVC). This paper briefly addresses | | | | users should receive some basic training to assist in |
| how each pipe rates in terms of the key design | | | | properly solvent welding pipe in these sizes. |
| factors. | | | | Environmental Effects - To get a true grasp of this |
| Flow Capacity - PVC and copper would each qualify | | | | issue, one should insist upon a Life Cycle Analysis on |
| to use a Mannings 'N' flow factor of.009 for gravity | | | | each piping material to capture all aspects of the pipe |
| flow while cast iron would typically require N=.013 to | | | | material's life from raw materials, to production |
| represent its rough interior. Net result means up to 33% | | | | processes, energy consumption, transport issues, |
| more carrying capacity for PVC and copper versus CI | | | | manufacturing locale, ease of recycling, waste product |
| when one considers actual inside diameters. | | | | generated and longevity. All three products have some |
| Longevity - CI is susceptible to many forms of | | | | drawbacks, specifically high energy costs for CI |
| corrosion including galvanic, electrolytic, acidic, moisture | | | | production and transport, very long distances of |
| induced, road salt attack and stray current effects. | | | | transport and a joining system involving open flames |
| Copper has better resistance but is still vulnerable to | | | | for copper, and a difficulty in using large amounts of |
| shortened life due to acidic attacks from aggressive | | | | recycled material in finished PVC DWV pipe due to |
| pipeline contents. PVC is virtually immune to all forms | | | | strict compound and high performance requirements |
| of corrosion and thus will outlast the other two, with | | | | of local building codes. PVC scores well for local |
| copper rating second best. | | | | manufacturing, in-house recycling of scrap PVC, low |
| Joint Tightness - CI is joined with rubber lined, metal | | | | energy consumption in production and transport, and |
| reinforced mechanical couplings which will adequately | | | | longevity. |
| meet industry standards and can be easily re-tightened | | | | Noise Generation - Both CI and PVC have superior |
| if required during a leaking field pressure test or while in | | | | sound deadening of drain flow than copper mostly due |
| operation. Both copper and PVC are more | | | | to thicker pipe walls. PVC offers much better sound |
| permanently joined through the soldering process for | | | | attenuation than the common ABS drain pipe used in |
| copper and solvent welding for PVC. Both of these | | | | most single family homes. CI benefits from its rough |
| joints could qualify as pressure-rated joints and helps | | | | interior to slow down flow velocities and its rubber |
| installers by permitting commission-testing of multiple | | | | couplings act as flexible shock absorbers. Designers |
| floors at once in buildings. | | | | agree that if noise suppression is an important concern |
| Certifications - All products must be third-party certified | | | | in building design, it is best addressed by specifying |
| to CSA or ASTM standards. CI must be certified to | | | | external pipe insulation to the DWV system regardless |
| CSA B70, copper to ASTM B306 and PVC to CSA | | | | of material. |
| B181.2. Both cast iron and copper are permitted in all | | | | Thermal Effects - For storm drains inside buildings, the |
| types of buildings while PVC must use a compound | | | | high rate of thermal conductivity for both CI and |
| (proprietary mixture of resin plus additives) listed by | | | | copper will warrant external insulation on the pipe to |
| ULC S102.2 to exhibit a Flame Spread Rating of not | | | | prevent condensation from occurring. PVC has a very |
| greater than 25 for all non-combustible construction. In | | | | low rate of thermal conductivity and as a result is |
| addition, PVC must be listed to also exhibit a Smoke | | | | many times used without insulation. It is common |
| Developed Classification of not greater than 50 for | | | | however to be conservative and use insulation for the |
| High-Rise Construction or Plenum installations. PVC is | | | | first several feet of the upper horizontal run of rain |
| not permitted in vertical shafts in most provinces. | | | | water leaders from roof drains. |
| Products are presently commercially available in the | | | | In conclusion, each of these materials CI, copper and |
| Canadian marketplace to meet these Flame and | | | | PVC offer some advantages and drawbacks |
| Smoke requirements. | | | | towards their use in commercial construction in |
| Capital Costs - Both CI and PVC score well here with | | | | Canada. Designers, contractors and building owners |
| stable competitive product pricing while copper tends | | | | are encouraged to consider all factors to ensure that |
| to be the most expensive and subjected to the high | | | | well-informed decisions are made. |