Backflow Protection by Air Gaps

Air Gap Required Locations
1. Use clothes washing and dish-washing machines that contain an air gap device in the machine.
2. Provide an air gap at the discharge point of any relief valve and any relief valve piping (such as a water heater temperature and pressure relief valve discharge pipe).

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Backflow Protection of Water Supply

Backflow and Cross-Connections Discussion
An important part of the design and use of the drinking (potable) water supply system is preventing contamination of potable water. Contamination can occur when the potable water supply is intentionally or unintentionally connected to a contaminant source. A cross-connection is a connection between the potable water supply and a potential contaminant source. Backflow is when material (usually liquid) travels in the reverse of the intended direction within a cross-connection. Contamination occurs when contaminated material backfl ows into the potable water system through a cross-connection. Some cross-connections are intended. Examples of intended cross-connections include toilet tank fill valves, automatic fill systems for swimming pools, and lawn irrigation systems.

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Backflow Protection Using Backflow Prevention Devices

Backflow Protection Device General Installation Requirements
1. Protect all drinking (potable) water supply openings, outlets, and connections by an air gap or by an approved backfl ow preventer. This means that any place from which water flows must have either an air gap or have a backfl ow preventer installed. Examples of openings, outlets and connections include sinks, bathtubs, showers, hose bibbs, and water supply connections to water and steam heating systems, irrigation systems, swimming pools, fountains, ponds, and similar water features.
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Fire Sprinkler System General Requirements

Limitations of the Material in this Section
The IRC provides detailed requirements for designing and installing residential fire sprinkler systems. Readers of this book should not att empt to design or install these systems. Consult qualified sprinkler system contractors when dealing with these systems. In this book section we present some general installation requirements to help readers bett er understand the nature and scope of residential fire sprinkler systems. Note that this requirement is very controversial and many jurisdictions do not require these systems. Verify with the local building offi cial if fi re sprinkler systems are required in your area.

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Reverse Osmosis Water Treatement Units

Air Gap for Waste Discharge
1. Install an air gap or a backflow prevention device between the reverse osmosis waste or discharge line and the connection to the plumbing waste pipe. The reverse osmosis unit manufacturer should provide an air gap faucet or a backfl ow prevention device to comply with this provision. The faucet or device should be labeled as meeting the requirements of NSF 58.

Water Service and Distribution Pipe General Installation Requirments

Water Pipe Installed in Contaminated or Corrosive Ground
1. Do not install water service or distribution pipe, fittings, valves, or other parts in soil or water that is contaminated with materials that may corrode or degrade the pipe or materials. The building official may require a soil analysis or may require alternate pipe routes or pipe materials if contaminated or corrosive soils are found or suspected.

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Water Supply General Requirements

Drinking Water Required
1. Provide each dwelling with a supply of drinking (potable) water.
2. Identify any sources of non-potable water that may be supplied in a building. Use color, metal tags, or other approved means to identify both the potable and non-potable supply pipes and fixtures.

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Water Supply Pipe Size

Limitations of the Material in this Section
Determining the correct size of water pipes requires knowledge of the water pipe material(s) to be installed (e.g., copper or CPVC pipe), the length of each part of the water pipe system, the height of each fixture above the water source (e.g., water meter or well head), the water demand requirements of each fixture and fixture group, the water supply pressure, and the pressure loss induced by appliances such as water meters, backflow preventers, water softeners, and water filters. This knowledge is beyond most readers of this book; therefore, we will not discuss in detail how to determine water pipe sizes. Leave calculation of correct water pipe size calculations to qualified contractors. We will present some basic information about how to calculate water pipe sizes and present an example of calculating water pipe sizes for an average home. Read the full Topic

Water Supply Valves

Water Supply Service Cutoff Valve
1. Provide each dwelling (including each unit of a two-family and townhouse building) with a water supply cutoff valve near where the water supply pipe enters the dwelling. Use a full-open type valve such as a gate or ball valve. Make this valve accessible.
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