Plumbing Design

Water Distribution

Water distribution piping for domestic use serves both hot and cold water needs in residential, commercial, and industrial applications. This type of piping is used for distributing potable water for everyday use within a building, such as drinking, washing, and other common purposes.

Material

Copper, PEX (cross-linked polyethylene), and CPVC (chlorinated polyvinyl chloride). In residential settings, copper piping is commonly used in mechanical rooms, while PEX is favored for other areas. In light commercial applications, copper piping is typically preferred.

Pipe Joining

Copper pipes are typically connected using either soldering or ProPress fittings. While soldering creates a stronger joint connection, ProPress fittings are often preferred for their ease of installation and repeatability, despite being more expensive. These fittings utilize a mechanical press to join copper pipes, with an EPDM (Ethylene Propylene Diene Monomer) O-ring embedded within each fitting to ensure a tight seal. In cleanroom and hospital applications, soldering may be prohibited due to flux off-gassing concerns, making ProPress fittings a more suitable alternative for these sensitive environments.

Wastewater

Wastewater piping and management are essential for efficient sewage and blackwater disposal, playing a critical role in maintaining a hygienic and safe environment. As a vital component of the drain-waste-vent (DWV) system, wastewater pipes ensure the proper removal of waste, contributing to overall sanitation and facility health. Effective wastewater management involves the design, installation, and maintenance of these piping systems, which help protect public health and the environment by safely transporting wastewater to treatment facilities or disposal sites.

Material

PVC, ABS, or cast iron. ABS is often preferred due to its affordability and durability. Cast iron, is often used in light commercial due to its strength; however, it’s more expensive and susceptible to corrosion.

Pipe Slope

The minimum slope for pipes with internal diameters of 2-½ to 4 inches is 1/4 inch per foot (2% slope). For pipes with internal diameters of 6 to 15 inches, the minimum slope is 1/8 inch per foot (1% slope).

Stormwater

Stormwater piping management is vital for controlling stormwater runoff, reducing flood risks, and minimizing erosion. Properly designed and installed stormwater systems channel excess water away from structures and surfaces, protecting property, infrastructure, and the environment from potential damage caused by heavy rainfall or storm events.

Material

Permeable concrete allows water to flow through, reducing runoff and promoting groundwater recharge. Another choice is corrugated metal, which provides durability and high strength, making it suitable for larger-scale applications. Lastly, high-density polyethylene offers a lightweight, corrosion-resistant material that is easy to install and provides flexibility.

Options

bioswales, channels, detention basins, green roofs, hydrodynamic separators, living walls, rain gardens, stormwater harvesting, swales, and other techniques.

Fire Protection

Fire protection piping is a critical component of both wet and dry sprinkler systems, which play a crucial role in addressing fire emergencies. These systems distribute water or other fire suppression agents throughout a building, helping to control and extinguish fires, thus minimizing damage and protecting lives.

Material

Wet sprinkler systems typically consist of steel or copper pipes, sprinkler heads, and water supply connections.

Dry sprinkler systems include similar components but require an air compressor to maintain the pressurized air within the pipes.

Types

Wet sprinkler systems remain constantly filled with water, ensuring immediate response in case of a fire incident.

Dry sprinkler systems are charged with pressurized air or nitrogen, these systems prevent water flow until activation. Upon activation, the air pressure drops, opening a valve, and allowing water to flow into the pipes and out of the activated sprinkler head. Dry systems are typically used in areas where freezing temperatures are a concern, such as unheated spaces.

Fuel Gas

Fuel gas piping is responsible for transporting combustible gases, such as natural gas, propane, and oil within a building. To ensure the safe and efficient operation of fuel gas systems, routine maintenance, and inspection are crucial for maintaining system integrity and addressing potential issues, such as leaks or corrosion. Additionally, adequate ventilation and proper clearances are essential for minimizing fire risks and guaranteeing a secure environment.

Material

Stainless steel or corrosion-resistant alloys are often used for fuel piping systems due to their durability, corrosion resistance, and ability to withstand various environmental conditions. These materials ensure a long-lasting and reliable piping system.

Pipe Joining

Soldering or brazing is commonly preferred for fuel gas piping. ProPress fittings are typically not recommended or approved for use in this context, as fuel gas piping requires secure and reliable connections to prevent leaks and ensure safety.

Specialty Piping

Specialty piping systems are essential for delivering and controlling highly regulated substances in healthcare, laboratory, and industrial settings. These systems must meet strict performance, safety, and material standards to ensure proper containment, flow, and functionality.

• Water treatment systems – deionized (DI), reverse osmosis (RO), acid waste

• Medical gas systems – oxygen, nitrous oxide N₂O, CO₂, vacuum

• Laboratory gases – compressed air, nitrogen, helium, argon, hydrogen

• Steam systems – distribution piping, pressure reducing valves, traps

Material

Specialty piping materials are selected based on the fluid or gas being transported, regulatory standards, and environmental conditions:

Medical gases: Use Type K copper tubing, cleaned and capped for oxygen service, in compliance with NFPA 99 and ASTM B819.

Laboratory gases: Use Type L copper or, in high-purity, high-pressure, or corrosive environments, 304 or 316L stainless steel for improved chemical resistance.

Water treatment systems (e.g., DI/RO, acid waste): Use CPVC, PVDF, polypropylene (PP), or 316L stainless steel, depending on fluid compatibility.

Steam systems: Use carbon steel for standard applications, or 304/316L stainless steel in corrosive or clean steam systems.

Pipe Joining

Joining methods vary depending on system requirements:

• Medical gases: Joined by brazing with nitrogen purge, as required by NFPA 99, to ensure clean, oxide-free internal surfaces.

• Laboratory gases: Use brazing (copper piping) or welding (stainless steel piping), with threaded or compression fittings used selectively depending on pressure and purity requirements.

• Plastic process piping (e.g., acid waste): Joined using heat fusion, electrofusion, or mechanical couplings.

• Steam piping: Typically joined by welding or flanged connections to handle thermal expansion and pressure. 

Each joining method must meet applicable code requirements (e.g., NFPA 99 for medical gases, ASME B31.3 for process piping) and be selected based on pressure, temperature, material compatibility, and service conditions.