6.0 PIPE MATERIALS
The most common inside building water distribution piping is copper. But this guide will cover other materials and their uses, properties, advantages and disadvantages.
There are other pipes available for use in the calculator but you can also add your own pipe information. The pipes built-in to the calculator include ASTM A53 Steel (Schedule 40 & 80), ASTM B88 Copper (Type K, L & M), ASTM D2241 PVC (SDR 26), ASTM F2389 Polypropylene (DR 9), ABS ASTM D1527, ABS ASTM D 2282, Brass Regular and Extra, CPVC ASTM F441 and F442, PEX, Ductile Iron, Galvanized Steel and Stainless Steel 304 & 316. These are the most common pipes used in chilled water pipe application. If you have a special case, then please use the references sheet to add in your pipe information or contact Justin via email email@example.com.
Figure 16: This figure is a sample of the pipe information built-in to the calculator, references tab.
Each pipe material and pipe type within that pipe material have its own standard pipe sizes. For example, Schedule 40 Steel does not have a 5/8 inch pipe size. When you change pipe materials and pipe types, please also change the pipe size to ensure the pipe size you want is available within the standard. The calculator will give you an error if you select a non-standard pipe size within the pipe material & type.
6.1 ABS PIPING
ABS stands for Acrylonitrile-Butadiene-Styrene. This piping is most often used for drainage, waste and vent systems and not used for domestic water systems. You can often see this pipe serving the waste for plumbing systems and it is often black. This piping is light and somewhat flexible and suitable for temperatures between -30 °F to 140 °F. Just like other plastic piping, ABS is not suitable for outdoor conditions when exposed to sunlight. The UV rays will degrade the ABS piping.
There are two standards that govern ABS piping, (1) ASTM D 1527 and ASTM D 2282. ASTM D 1527 is titled Standard Specification for Acrylonitrile-Butadiene-Styrene (ABS) Plastic Pipe, Schedules 40 and 80. ASTM D 2282 is titled Acrylonitrile-Butadiene-Styrene (ABS) Plastic Pipe, SDR-PR. These two standards give the dimensions and tolerances for the various ABS pipe types.
6.1.1 ASTM D 1527 SCHEDULE 40 & SCHEDULE 80
The pipe schedule describes the thickness and pressure rating for each pipe size. Schedule 80 has thicker walls than schedule 40 and thus schedule 80 piping has a higher pressure rating than schedule 40 piping. Schedule 40 and Schedule 80 piping have the same outside diameter, but their thicknesses are different. The schedule 80 piping has a greater thickness, which makes the inside diameter smaller when compared to schedule 40 piping.
Table 4: This table shows the pipe dimensions for schedule 40 ABS plastic piping in accordance with ASTM D 1527.
Pipes will typically have the same outer diameter, because this allows pipes of different schedules to be joined together. As you can see, schedule 80 piping has the same outer diameter as schedule 40 piping for each specific pipe size. However, the inner diameter is smaller because the schedule 80 pipe has thicker walls.
Table 5: This table shows the pipe dimensions for schedule 80 ABS plastic piping in accordance with ASTM D 1527.
6.1.2 ASTM D 2282 STANDARD DIMENSION RATIO (SDR)
The Standard Dimension Ratio or SDR describes the relationship between the pipe outer diameter and the thickness of the pipe wall.
For example, SDR 17 for an outside diameter of 1.315 inches will have a pipe thickness of 0.077 inches and 0.063 inches for SDR 21.
Table 6: ABS pipe type SDR 26 pipe sizes
Table 7: ABS SDR 14 pipe sizes
Table 8: ABS SDR 13.5 pipe sizes
6.1.3 PRESSURE RATINGS
The pressure ratings for ABS piping are determined by the pipe diameter, pipe thickness and the pipe material. Although the pipe material is ABS, there are different classes within the overall ABS pipe material family. The typical ABS pipe classes include ABS2112, ABS1316, ABS1210 and ABS1208. ABS 2112 is the strongest, then ABS1316, followed by ABS1210 and finally ABS1208. The burst pressure for these materials and SDR combinations are shown below.
6.2 BRASS PIPING
Brass piping is in some cases an approved potable water piping and was popular in the past, but it has been replaced by materials that are easier to work with and usually provide longer service. There are two types of brass piping, (1) regular strength and (2) extra strength. The extra strength brass has thicker walls, which allows this pipe to have a higher allowable working pressure. The table below shows the dimensions of brass regular and extra strength piping. As you can see the inner diameter for extra strength piping is slightly less than the equivalent regular strength pipe size. This is due to the increased pipe thickness.
6.2.1 REGULAR STRENGTH
Table 9: This table shows the dimensions of regular strength brass piping.
6.2.2 EXTRA STRENGTH
Extra strength piping is typically not used for domestic water systems, since the pressures in domestic water systems typically never exceed 300 psi and the regular strength brass piping has sufficient strength to withstand 300 psi. The following two tables show the maximum allowable pressure for both regular and extra strength piping to further explain this point. As you can see, the maximum allowable pressure decreases with an increase in temperature.
Table 10: This table shows the dimensions of extra strength brass piping.
6.2.3 PRESSURE RATINGS
Table 11: The maximum allowable pressure decreases as the temperature of the fluid increases.
Table 12: The extra strength brass piping has much higher maximum allowable pressures as shown in the below table.
6.3 CPVC PIPING
Chlorinates Polyvinyl Chloride (CPVC) is a plastic piping that is used to distribute cold water and sewer, waste, vent systems. Its main benefit is that it is low cost and easy to install. It is suitable for pressurized cold water (73 F) at pressures up to 300 PSI for smaller diameters and thicker pipes. However, at higher temperatures (180 F) the pressure rating drops down to 100 PSI and lowers for thinner pipes and larger diameters.
CPVC is slightly stronger than PVC and can handle higher temperatures. However, CPVC cannot handle temperatures as high as copper piping. In addition, CPVC has a larger coefficient of thermal expansion than metal piping. This means that you will need to account for pipe expansions and reductions for long runs of CPVC piping.
There are two standards that govern the dimensions of CPVC piping. These standards are ASTM F441 and ASTM F442. The first standard provides dimensions in the Schedule format and the second standard in the SDR format.
6.3.1 ASTM F441 STANDARD SPECIFICATION FOR CHLORINATED POLY VINYL CHLORIDE (CPVC) PLASTIC PIPE, SCHEDULES 40 AND 80
Table 13: This table shows the dimensions for CPVC Schedule 40 piping.
Table 14: This table shows the dimensions for CPVC Schedule 80 piping.
The pressure rating of the piping ranges from 1,130 PSI for Schedule 80, 1/4” pipe down to 230 PSI for Schedule 80 12” pipe and 210 PSI for Schedule 80 24” piping. The pressure rating also ranges from 780 PSI for Schedule 80 ¼” piping down to 220 PSI for 4” Schedule 40 piping and even further down to 120 PSI for 24” Schedule 40 piping. As you can see the pressure rating (maximum allowable water pressure) decreases as the size of the piping is increased and the pressure rating for schedule 80 piping is higher than the pressure rating for Schedule 40 piping.
The pressure rating is also de-rated as the water temperature increases. The previous pressures are based on 73 F water temperature. The pressure rating is de-rated down to 20% of the pressure rating when the water temperature is 200 F. The pressure ratings for piping are readily available from pipe manufacturer’s websites. But as a designer you should understand that CPVC is not suitable for high temperature water at pressures greater than 100 PSI and even lower for larger pipe sizes.
6.3.2 ASTM F442 STANDARD SPECIFICATION FOR CHLORINATED POLY VINYL CHLORIDE (CPVC) PLASTIC PIPE, SDR-PR
Similar to ABS piping, CPVC can also be rated in the SDR format. However, most manufacturers in the United States do not use this format. Thus these pipe sizes are not included in this guide nor are these pipe sizes included in the calculator.
6.4 COPPER PIPING AND TUBING
6.4.1 DIFFERENCE BETWEEN PIPING AND TUBING
Piping is primarily used as a fluid carrier and is measured by inside diameter (ID). Thus when a ½” nominal copper pipe is selected, the inside diameter is roughly ½” while the outside diameter is 0.625 inches. Tubing is primarily used for structural purposes and is measured by outer diameter (OD). A ½” copper tube has an outer diameter of 0.545 while its ID is less than ½”. In domestic water piping systems, copper tubes are used and not copper pipes.
6.4.2 COPPER TYPES
There are six standard types of copper and are shown below for reference, you should select the type that most closely matches your project’s situation:
6.4.3 TYPE K COPPER TUBING
Type K copper tubing is commercially available in 20 ft lengths, drawn or annealed. It can be used for domestic water, fire protection, fuel, fuel oil, refrigerants, compressed air, LP gas and vacuum. It has the thickest walls of types L and M. Type L walls are thicker than Type M. These relations hold true for all pipe diameters. The outside diameters for each type, only the inside diameters and wall thicknesses vary for each type.
This type of pipe is most often used for below ground installations or when damage can occur to an above ground installation and a harder material is required.
Table 15: Type K Copper Tubing Table
6.4.4 TYPE L COPPER TUBING
Type L copper tubing is commercially available in 20 ft lengths, drawn or annealed. It can be used for domestic water, fire protection, fuel, fuel oil, refrigerants, compressed air, LP gas and vacuum. It has the second thickest walls of Types K, L and M.
This type of pipe is most often used for above ground installations and when possible damage is not likely to the above ground installation.
Table 16: Type L Copper Tubing Table
6.4.5 TYPE M COPPER TUBING
Type M copper tubing is commercially available in 20 ft lengths, drawn or annealed. It can be used for domestic water, fire protection, fuel, fuel oil, refrigerants, compressed air, LP gas and vacuum. It has the thinnest walls of Types K, L and M.
Table 17: This table shows the pipe dimensions for Copper Type M tubing.
6.4.6 TYPE DWV COPPER TUBING
Type DWV: This type has the thinnest walls and is used in drain, waste, vent applications where little to no pressure is involved. This type should not be used for pressurized water, so it is not included in the Domestic Water Piping Calculator.
6.4.7 TYPE MEDICAL GAS COPPER TUBING
Type Medical Gas: This type has an internal cleanliness requirement that meets the standards for piping conveying oxygen, nitrogen, nitrous oxide, medical compressed air or other gases used in medical facilities. This type should not be used for pressurized water, so it is not included in the Domestic Water Piping Calculator.
6.4.8 PRESSURE RATINGS OF COPPER TUBING
Pressure Ratings: The pressure rating of copper piping is very suitable for domestic water systems, since the pressure typically never exceeds 300 psi in a building. Water pressure can exceed 300 psi in high rise buildings.
Table 18: Type K is the strongest copper pipe and thus has the highest allowable pressure. Although Type K piping is typically used for underground domestic water piping, you should also use this type when you have pressures exceeding 150 psi and larger pipe diameters.
Table 19: Type L tubing is the 2nd strongest copper type. This pipe is typically used for indoor tubing and where pressures do not exceed 150 psi for larger tube diameters.
Table 20: Type M is the weakest of the three copper pipe types and should be used very carefully.
6.5 PEX PLASTIC PIPE AND TUBING
Cross-Linked Polyethylene or PEX piping’s main advantage is a plastic, polyethylene pipe or tube. This material is flexible, which means that the installation cost is lower than other piping. Crosslinking is a chemical reaction that links one polyethylene polymer chain to another. There are three main classifications of PEX piping, PEX-a, PEX-b and PEX-c. The different classifications describe the method of crosslinking. Each method meets ASTM F 876 and ASTM F 877, which determines the dimensions, pressure ratings and temperature ratings. However, the cost of each type is slightly different and the flexibility of each type is different.
The other classification of PEX pipes is whether or not the pipe has a barrier. Typically domestic water systems use non-barrier type PEX piping. The barrier refers to a laminated surface that is placed on the outside of the pipe, which restricts oxygen from entering the fluid. This is used for hydronic systems and other non-potable water systems.
Lastly, PEX cannot be used outdoors because it cannot withstand UV rays, unless it has a UV coating. Designers do not like to risk a pipe’s life on a coating, so PEX will not be used outdoors, similar to other plastic piping.
ASTM F 876 is the standard that specifies the material properties and the dimensions for PEX tube. ASTM F 877 is the standard that specifies the performance requirements for a PEX system, tube and fittings together. PEX tube is typically manufactured according to SDR-9. The dimensions for PEX SDR-9 are shown in the below table. The manufacturing method does not matter for the dimensions, since PEX-a, b, c are all manufactured to the same dimensions.
Table 21: This table shows the dimensions for PEX SDR-9 piping.
PEX piping is only used for smaller distribution pipes, up to 1” but some manufacturers do provide piping up to 2”.
6.5.1 PRESSURE RATINGS
PEX tubing typically has a maximum allowable water pressure of 160 PSI at 73 F, 100 psi at 180 F and 80 PSI at 200 F.
6.6 DUCTILE IRON WATER PIPE
Ductile iron is typically used by civil engineers as underground main piping. This pipe is not normally used by mechanical engineers for the building domestic water piping. This piping is suitable for underground, larger pipes because of its very long life. The piping is designed to last typically more than 100 years. The pipe is very strong and durable, so it can also withstand pressure loadings from being under roads and also any possible damage during handling and installation. Ductile iron is stronger than carbon steel piping and is also easier to work with, hence the name, ductile.
Ductile iron is an iron, so it is susceptible to corrosion. Linings are usually provided to slow down corrosion, but this will add cost to the piping. Ductile iron is relatively more expensive than its plastic counterparts.
Ductile Iron has different pressure classes. These classes identify the allowable water pressure. These classes include, 350 PSI, 300 PSI, 250 PSI, 200 PSI and 150 PSI. The outer diameters for each of the classes are the same, but the inner diameters are adjusted as the thickness changes for each pipe class. The higher pipe classes have increased thickness and smaller inner diameters.
The dimensions for these pipe classes are shown in the Domestic Water calculator.
6.7 GALVANIZED STEEL PIPING
Galvanized steel piping is in some cases an approved potable water piping but it is difficult to work with and subject to rust, which can cause leaks, decreased pressure and reduced flow.
Table 22: This table shows the dimensions of galvanized steel, schedule 40 pipes.
Table 23: This table shows the dimensions of galvanized steel, schedule 80 pipes.
6.7.1 PRESSURE RATINGS
The pressure rating for galvanized steel pipes vary based on the pipe size and schedule. The thicker schedules have higher pressure ratings and so do the smaller pipes. The maximum allowable pressure ranges from 2,000 psi for small pipes down to 200 psi for larger pipes and lower schedules. The pressure ratings are suitable for temperatures ranging from 0 F to 300 F.
6.8 POLYETHYLENE AND POLYPROPYLENE PLASTIC PIPING AND TUBING
Polyethylene and polypropylene are types of thermoplastic materials. These materials are not used as often for domestic water systems. These materials are typically used for fluids that are not chemically compatible with metal pipes. In addition, these materials can be used when corrosion is a concern, since plastic piping does not corrode. Plastic piping is also used because it is much cheaper and easier to work with than metal pipes.
However, these plastics are not as long lasting as their metal counterparts and do not do well when exposed to UV, unless the plastic has a UV coating. Some polyethylene pipe can be constructed with UV resistance built-in. In addition, plastic piping expands/contracts more drastically with changes in temperature and also has a much lower pressure rating than metal piping, especially at high temperatures.
Polyethylene (PE) and Polypropylene (PP) piping can range from sizes ½” to 65” but the calculator only includes the smaller pipe sizes since these are the most common for domestic water systems.
There are different types of PE and PP materials. These different types are usually given a four digit material code. The first two digits classify the cell, which determines the material’s density, tensile strength, slow growth crack resistance and much more. The second two digits determine the recommended standard hydrostatic design stress category. This is the basis used to determine the long-term strength of the pipe.
The applicable standards for polyethylene and polypropylene piping are (1) ASTM D 2239, (2) AWWA C901 and ASTM D 2737. ASTM D 2239 is titled the Standard Specification for Polyethylene (PE) Plastic Pipe (SIDR-PR) Based on Controlled inside Diameter. AWWA C901 is titled Polyethylene (PE) Pressure Pipe and Tubing, ½ inch through 3 inch for Water Service. AWWA stands for the American Water Works Association. ASTM D 2737 is titled the Standard Specification for Polyethylene (PE) Plastic Tubing. ASTM F 2389 is titled the Standard Specification for Pressure-rated Polypropylene (PP) Piping Systems.
6.8.1 PIPE DIMENSIONS
There are two ways that the pipe dimensions can be expressed for these plastic pipes, (1) SIDR and (2) SDR. SDR or standard diameter ratio was previously discussed with ABS and CPVC piping. SIDR stands for standard inner diameter ratio, which is the ratio of the inner diameter to the pipe thickness. SIDR is used for smaller pipes and for a special joining method that uses insert fittings. Thus the outside diameter can be varying, but the pipes can be joined as long as their inner diameters are the same.
Table 24: This table shows the pipe dimensions for plastic SIDR7 piping. A lower number indicates a greater pipe thickness.
Table 25: This table shows the pipe dimensions for plastic SIDR9 piping. The higher number indicates a smaller pipe thickness. As you can see, the inner diameter is the same as SIDR7, but the thickness is smaller.
The second method that the plastic pipe dimensions can be shown is through the SDR or DR method. In this method, the outer diameters are the same and the inner diameters vary.
Table 26: This table shows the plastic DR7 pipe dimensions.
Table 27: This table shows the plastic DR9 pipe dimensions.
The calculator also has the following plastic pipe types, DR11, DR13.5, SIDR11.5, SIDR15, and SIDR19. The calculator only includes smaller pipe sizes for these plastics, because these are the sizes that are most common for domestic water systems.
6.8.2 PRESSURE RATINGS
The pressure ratings for plastic piping are much lower than metal piping. The pressure ratings range from 160 psi to 63 psi for the various pipe types. Also these pressure ratings are only for 73 F and the pressure ratings will drop as the temperature increases.
Table 28: Maximum allowable pressure for plastic piping
There are different material types within the overall PE and PP piping categories and each sub-material type will have slightly different maximum allowable pressures. So be sure to use these pressure ratings only as a guide and to check with the pipe manufacturer for the exact pressure ratings, based on the pipe temperature, pipe size, pipe type and sub-material type.
6.9 POLYVINYL CHLORIDE (PVC) PIPING
PVC piping is typically used for drainage, waste and vent systems and irrigation systems. PVC piping can be exposed to UV rays unlike most other plastic piping. This piping is cheaper, lighter and easier to join, compared to metal piping.
The applicable standards are (1) ASTM D 1785 and (2) ASTM D 2241. ASTM D 1785 is titled Standard Specification for Polyvinyl Chloride (PVC) Plastic Pipe, Schedules 40, 80, and 120. ASTM D 2241 is titled Standard Specification for Polyvinyl Chloride (PVC) Pressure-Rated Pipe (SDR Series). These standards govern the dimensions shown in the next section.
There are different types of PVC piping, PVC 1120, 1220, 2120, 2116, 2112 and 2110. These different types of PVC have slightly different material properties like density, strength, slow growth crack propagation, etc. Each sub-material type will have slightly different pressure ratings, but the dimensions will be the same for each sub-material type.
6.9.1 PIPE DIMENSIONS
There are two ways that the pipe dimensions can be expressed for these PVC pipes, (1) SDR and (2) Schedule.
The main SDR types are SDR 17, 21, 26 and 32.5. The lower SDR values have larger thicknesses and larger pressure ratings.
Table 29: This table shows the dimensions of PVC SDR 17 piping.
Table 30: This table shows the dimensions of PVC SDR 21 piping. SDR 21 piping has a smaller inner diameter
The calculator also includes SDR 26 and SDR 32.5. The two main schedule types are Schedule 40 and Schedule 80. Schedule 10 and 120 piping is also available but these are less common and are not included in the calculator.
Table 31: This table shows the dimensions of PVC Schedule 40 piping.
Table 32: This table shows the dimensions of PVC Schedule 80 piping.
6.9.2 PRESSURE RATINGS
The various PVC sub-material types and SDR’s has pressure ratings from 50 to 315 psi. The lower SDR’s have higher pressure ratings and the higher SDR’s have lower pressure ratings. Schedule 40 piping has a pressure range from 810 psi down to 60 psi, depending on PVC sub-material type and pipe size. The smaller pipe sizes have greater pressure ratings. Schedule 80 piping has a pressure range from 1,230 psi down to 60 psi, depending on PVC sub-material type and pipe size.
As the temperature increases, the pressure rating also decreases. The pressure rating decreases by nearly 22% when the temperature is increased from 73 F to 140 F. There are different sub-material types within the overall PVC piping material category and each sub-material type will have slightly different maximum allowable pressures. So be sure to use these pressure ratings only as a guide and to check with the pipe manufacturer for the exact pressure ratings, based on the pipe temperature, pipe size, pipe type and sub-material type.
6.10 STAINLESS STEEL PIPING
Stainless steel piping is not often used for domestic water systems due to its cost. Stainless steel is suitable for conditions where corrosion resistance is required. Although the name stainless implies that the pipe will not corrode, but it only means that the pipe is more resilient than other metals. The key to its corrosion resiliency is the chromium. Stainless steel is a steel alloy that is comprised of at least 10.5% chromium. A steel alloy is the combination of iron and another element, in this case chromium.
There are two main types of stainless steel piping and they are 304 and 316 stainless steel. The difference between 304 and 316 is the chemical composition. 304-stainless steel contains iron and (10.5%) chromium. 316-stainless steel contains iron, (10.5%) chromium and (2-3%) molybdenum.
There is another distinction added for stainless steels. A stainless steel will have other elements besides iron and chromium. For example, this is the typical composition of 304-stainless steel.
Table 33: The percent composition of typical 304 stainless steel.
A stainless steel can be distinguished with an “L” at the end of its number designation. This indicates that the stainless steel has a carbon percentage that is less than .04%. This low level of carbon increases the metals corrosion resistance. 304 or 316 stainless steel is more likely to corrode at weld locations, but 304L or 316L will have more corrosion resistance at weld locations.
In summary there are four main types of stainless steel pipe materials, (1) 304, (2) 304L, (3) 316 and (4) 316L. These materials are excellent for locations where corrosion is a concern.
6.10.1 PIPE DIMENSIONS
The pipe dimensions are the same for 304 and 316-stainless steel. The pipe dimensions only change with the various pipe sizes and schedules. ASTM A312 is titled Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes. This specification shows the outer diameters and the thicknesses required to meet the various schedules, 10S, 40S and 80S. Schedule 10S is the thinnest pipe and 80S is the thickest pipe. The outer diameters are the same for each schedule, but the thicknesses vary. Constant outer diameters allow pipes of different schedules to be connected to each other.
Table 34: This table shows the dimensions for schedule 10s stainless steel piping
Table 35: This table shows the dimensions for schedule 40s stainless steel piping.
Table 36: This table shows the dimensions for schedule 80s stainless steel piping.
6.10.2 PRESSURE RATINGS
Stainless steel pipes have pressure ratings that vary based on the type, pipe size and schedule. The thicker schedules have higher pressure ratings and so do the smaller pipes. Similar to the other previously discussed metal piping, stainless steel piping has a maximum allowable pressure ranging from 2,000 psi for small pipes down to 200 psi for larger pipes and lower schedules. The pressure ratings are suitable for temperatures ranging from 0 F to 300 F. The 304 pipes will be stronger, since it has more iron and the 316 will be weaker.