Malleable iron pipe fittings, due to their superior sealing performance, mechanical strength, and mature manufacturing process, have a clear and important application in low-pressure gas transmission, especially in residential and commercial gas supply networks. They are primarily used for pipe connections between the gas meter and the appliance.
Their advantages are prominently reflected in the following aspects: First, extremely reliable sealing. The precision tapered pipe thread (Rc/R) connection forms an interference fit between the metal surfaces after tightening, achieving a rigid seal that is crucial for preventing even minor leaks of this hazardous medium. Second, high mechanical strength and resistance to external forces. The malleable cast iron material is robust and durable, resisting mechanical impacts and stresses during installation and use. The pipe supports are stable, resulting in a long service life. Third, satisfactory corrosion resistance. The hot-dip galvanized surface effectively resists atmospheric and general environmental corrosion, ensuring long-term safety.
However, strict adherence to regulations is essential in gas applications: First, they are limited to low-pressure systems (usually referring to indoor pipes with pressure below 5 kPa) and are strictly prohibited from use in medium- and high-pressure main pipeline networks. Secondly, all pipe fittings must be specialized galvanized gas fittings, with coating quality and thickness requirements typically higher than those for ordinary water fittings. Most importantly, special sealing fillers such as PTFE tape must be used during connections; the use of materials that may clog pipes, such as paint or hemp fiber, is absolutely prohibited.
In short, the correct selection and standardized installation of malleable iron pipe fittings is a crucial link in ensuring a safe, economical, and reliable connection for low-pressure indoor gas systems, but their application must be strictly limited to the permitted scope and conditions specified in the regulations.
Post time: Dec-31-2025