Bonding and Installation Requirements for CSST Gas Piping Systems April 2009

A conducting connection between an electrical circuit or equipment and the earth that limits the voltage imposed upon it. Only the premise wiring system is grounded. The permanent joining of metallic parts to form an effective electrical path that ensures continuity and the capacity to safely conduct any current likely to be imposed. Gas piping is bonded. Grounding verses Bonding

Grounding Requirements Grounding system limits power surge and lightning energy Grounding required at transformer as well as house NEC requirement

Ave. number lightning flashes/year in US: 25,000,000 Average annual number of U.S. home fires * by cause: - Fires caused by lightning: 4,800 - Fires caused by natural gas: 2,100 - Fires caused by lightning/fuel gas: Fires caused by lightning/wires: Fires caused by electric distribution: 24,000 Lightning damage to gas piping is an uncommon event compared to other causes of fires. * NFPA data Lightning Statistics

Insulation failure on power circuit wiring Unintentional contact with higher voltage line Direct lightning strike on the structure Lightning that branches from nearby strike Lightning energy conducted through the soil and underground metallic systems or through overhead power lines Lightning current takes all pathways of electrical resistance to ground and not just the path of “least resistance”. Energizing Metallic Piping Systems

Lightning does not discriminate. It will damage all piping materials and systems. Damage is attributed to arcing caused by a difference in voltage build-up between the grounded electrical system and any other electrically conductive pathway. Gas system components typically damaged: –Perforations of CSST wall –Flow/loss of pipe dope between threaded joints –Failure of flexible connectors on steel pipe system –Failure of copper tubing/pipe –Failure of gas burning equipment components Lightning Induced Piping Damage

Lightning Induced CSST Damage Arcing damage impacts all gas piping materials CSST does not fail due to lightning induced voltage levels Thinner pipe wall is a contributing factor

NFPA 780: Lightning Protection System Protects structure LPS effective against indirect strikes through its grounding electrode system Lightning activity varies around country Bonding of underground metal piping required by NFPA 780

Contributing Construction Factors Metallic duct work not typically bonded Elimination of other metallic pathways: –No copper water pipe (use of PEX) –Less or no coax cable (wireless communications) –Non-metallic plumbing vents and drains Replacing masonry chimneys with metallic appliances vents – new lightning pathway that energizes wire, duct and pipes

Increase robustness of bonding connection beyond minimum required by NEC. Bonding at service entrance to divert energy off gas piping system and lower voltage level. Increase jumper size to reduce the difference in voltage build-up between other electrically conductive pathways and minimize potential for arcing. Equi-potential bonding of all metallic systems will further reduce the chances for arcing by balancing the voltage levels in all connected systems. Maintain physical separation as much as practical CSST Solution

Applicable Codes and Standards

(B): Other Metallic Piping: Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with using the rating of the circuit that is likely to energize the piping system(s). The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means. Section (B) only deals with electrical energy at 60-Hz and only provides ground fault protection. NEC Bonding Requirements

Grounding Electrode System Various types of electrodes permitted Grounding electrode conductor and bonding conductor are different Do not install separate electrode for gas service

Equipment Grounding Conductor EGC sized to protect against ground faults 12 AWG wire not able to carry electrical energy from lightning 12 AWG wire not able to respond to lightning frequencies

2009 Bonding Requirements* CSST gas piping systems shall be bonded to the electrical service grounding electrode system at the point where the gas service enters the building. The bonding jumper shall not be smaller than 6 AWG copper wire or equivalent. * 2009 NFPA 54, IFGC and UPC

2009 IFGC Electrical Isolation Isolation. Metallic piping and metallic tubing that conveys fuel gas from an LP-gas storage container shall be provided with an approved dielectric fitting to electrically isolate the underground portion of the pipe or tube from the above ground portion that enters a building. Such dielectric fitting shall be installed above ground, outdoors. Proposal submitted for 2011 NFPA 58.

CSST manufacturer has no enforcement power. Reliance on product listing and manufacturer’s instructions varies. State/local code may not be in sync with national model codes. NEC Section 110.3(B) and NFGC Section defers to the manufacturer’s instructions for listed equipment if code not clear. Subject to interpretation by local AHJ. Local Code Enforcement

Complete Piping System - Tubing - Fittings - Strike Plates Update ANSI Standard Installed in accordance with manufacturer’s instructions Uniform bonding practices Impact on CSST Piping Systems

Ward Mfg - Wardflex Parker - ParFlex Omegaflex - TracPipe Titeflex - Gastite Truflex - Pro-Flex MetalFab - Diamondback Six Manufacturers: One Approach

Technical Bulletins

Direct bonding of CSST to the grounding system is now required All new CSST installations for all gas appliances One-size-fits-all for most residential applications Installation and sizing requirements consistent with NEC Section 250 for metallic piping and current edition of NFGC Installed by person recognized by AHJ as qualified to perform such work Do not bond any underground metallic piping upstream of utility meter CSST Bonding Instructions

One simple, universal bonding approach Effective and low cost Consistent with NEC/NFGC requirements Applies to all single family and low-rise multi-family Commercial applications may require an engineered solution KISS Principle

Electrical service equipment enclosure Grounded conductor at the electrical service Grounding electrode conductor Grounding electrode Direct Bond Connection

Customer side of meter Downstream of 2 nd stage LP regulator Indoors or outdoors Upstream of first CSST fitting Bond Near the Gas Service

Bond Upstream of 1 st CSST Fitting

Multi-Meter Bonding

At least a 6 AWG copper wire or equivalent Installed in accordance with NEC Jacketed or bare Above or below grade Keep as short as possible Bonding Jumper

Attachment Points Between meter and first CSST fitting Attached to pipe or pipe component per the clamp listing Never attach to corrugated tubing itself Insure metal-to-metal contact between clamp and sub-surface

Listed to national standard UL 467 Attached in accordance with NEC and listing Always accessible Bonding Clamp

Avoid using other metallic systems for support Avoid direct contact with other metallic systems Avoid co-locating CSST with metallic appliance vents Avoid Physical Contact

Plumbing inspector must look for presence of bonding on new systems and reject system without proper connection. Alert plumbing contractor of requirement. Electrical inspector must inspect to NEC minimum ( B) and in accordance with the CSST manufacturer’s instructions. On retrofit jobs, plumbing inspector must either notify electrical inspector or inspect bonding. Inspector Responsibility

Direct bonding of gas piping will: –Lower voltage levels –Reduce differences in electrical potential –Minimize the possibility of arcing Maintain physical separation where practical Bonding together of all metallic systems All CSST products require the same type of bonding in accordance with current edition of NFPA 54 or IFGC or UPC Summary

No code or standards requirements mandating lightning resistance, protection or mitigation. New bonding requirements above minimum of NEC. Direct bonding will reduce impact of lightning strikes on gas piping system without effecting ground-fault protection. CSST industry requiring direct bonding on all new CSST installations with a “keep-it-simple” approach. National model code change proposals are being developed. CSST product standard being updated. Conclusions

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