New Requirements for CSST Installation

格雷戈里·哈夫（Gregory Havel）的文章和照片

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使用波纹不锈钢管上衣ted with yellow PVC or polyethylene (CSST) as piping for natural and LP gas has been growing rapidly since its introduction in 1989. This is because of the greatly reduced installation labor compared to using conventional black pipe with threaded fittings. Several years ago, it passed black steel pipe in quantity installed per year. Photo 1 shows a natural gas service entering a building, with a field-assembled manifold for connecting CSST to serve three gas appliances, plus a run of black pipe serving another manifold on the other side of the building. (Since the connection to the contractor’s heater is only temporary, the bonding clamp and conductor have not yet been installed.)

CSST has been extensively tested, and has received approval for meeting the requirements of several codes and standards:

• NFPA 54:国家燃气法规
• NFPA 58：液化石油燃气法规
• ICC：国家机械法规
• ANSI LC-1-2005：Fuel Gas Piping Systems Using Corrugated Stainless Steel Tubing

According to literature and instructions from the manufacturers, CSST systems must be installed by qualified installers who are trained in the methods required by that brand’s system, and who meet all of the qualifications of the state and local codes and of the authority having jurisdiction where the CSST is installed. However, we must be aware that this material is also available to do-it-yourself installers at hardware and home supply stores, where the only training provided is an installation manual that is often sold separately. We must also be aware that the instructions are not always followed; and that substandard temporary installations sometimes become permanent.

（1）点击放大

For several years, there have been reports of damage to CSST installations in buildings that were struck by lightning, including breaks in the tubing and ignition of the fuel gas and the surrounding structure. The early reports were not always considered credible, even though firefighters recognized the breaks in the system and the burning gas. It was noted that this damage could be due to the small mass of CSST compared to black steel pipe. As the documented history of these incidents developed, tests were conducted which proved that lightning could damage CSST gas piping, and which suggested a way to reduce the possibility of lightning damage.

（2）点击放大

2009年的NFPA 54，国家燃气法规，包括将CSST燃气管道系统粘结到建筑物电气系统的接地导体的新要求，以通过降低金属物体和建筑系统（包括气体分布）之间的电势来减少雷击的可能性。

“7.13.2 CSST. 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.”

“ 7.13.3禁止使用。气管不得用作接地导体或电极。这并不排除金属管道与接地系统的键合。”

“ 7.13.4*闪电保护系统。在安装避雷针系统的情况下，燃气管道的粘结应符合NFPA 780，Standard for the Installation of Lightning Protection Systems.”

将CSST气体分配系统结合起来，需要在系统的安装程序，电工和避雷针安装程序之间进行合作，如果建筑物有建筑物。

CSST制造商的说明和其他文献现在包括NFPA 54的这些粘结要求。一些制造商还建议升级现有的CSST系统以包括所需的键合。

Approved methods of bonding require the installation of a UL-listed ground clamp:

• on the black steel gas pipe where it enters the building; or
• on the manifold connecting the black steel gas pipe to multiple runs of CSST; or
• on the brass fitting connecting each run of CSST to a manifold.

粘合导体必须是6号或较大的铜线，固体或滞留，连接到UL上固定的接地夹上的端子。粘结导体必须是连续的，另一端连接到

• 电气服务设备的钢封面；或者
• The grounded conductor at the electrical service; or
• 服务设备和接地电极之间的接地电极导体（如果足够大）；或者
• 电气系统的一个或多个接地电极（“接地杆”）。

CSST必须仅在最接近天然气服务进入建筑物的末端进行粘合。如果在两端或最接近气体燃烧设备的末端粘结，CSST可能会携带流浪电流或充当接地导体，从而损坏CSST及其配件，并导致泄漏。

照片2显示了一项气体服务，该气体已通过新房屋的墙壁作为黑色钢管，并附有CSST的连接器，将气体带到炉子和热水器中。粘结夹和粘结导体已经连接到黑色管道上。粘合导体的另一端将连接到电动服务面板内的接地杆，该电动服务面板已经连接到两个接地杆和水表附近的铜冷水管。

这项新的安全要求将需要对消防检查员和建筑检查员进行培训更新，他们可能只熟悉代码要求，这些代码要求不得将煤气管道用于接地目的；对于可能被教导要在遇到煤气管中去除地面夹的公用事业工人。

Subjects:Building construction for firefighters, natural gas and liquefied petroleum gas piping, CSST