Plate type flat welding flange, abbreviated as PL flange, is the most cost-effective and convenient pipeline connection flange in the domestic HG/T20592 and GB/T9112 national standard systems. With the advantages of plug-in corner welding, no need for pipeline groove welding, and low cost, it has become the most commonly used flange category in low-pressure and room temperature pipeline networks. Many procurement and engineering technicians often confuse the usage boundaries of plate welding flanges and neck welding flanges. This article combines domestic industrial standards to explain in detail the industry scenarios, applicable working conditions, and prohibited scenarios where plate welding flanges are most commonly used, in order to accurately avoid selection errors. At the same time, Shanghai Hongguan Stainless Steel Flanges provide various materials of flanges. Welcome to inquire!

1、 Top 4 industries in terms of usage of flat welding flanges (concentrated usage, preferred for rigid needs)

1. Municipal water supply and drainage industry (ranked first in national usage)

The municipal industry is the largest application area for flat welding flanges, which are fully compatible with urban water supply pipelines, municipal sewage and rainwater pipelines, pump station units, water plant clean water pipelines, and outdoor fire protection pipelines. The working conditions are uniformly PN10 and PN16 low pressure levels, with room temperature clean water and sewage media. The pipeline vibration is minimal and the pressure fluctuation is stable. Almost all large-diameter pipelines (DN300-DN2000) use carbon steel plate flat welding flanges, which have low construction costs and high welding efficiency, and are suitable for large-scale municipal pipeline construction.

2. Chemical industry utility system (preferred low-pressure flange for chemical industry)

The chemical industry strictly prohibits the use of flat welding flanges for flammable and explosive process pipelines, but the public engineering systems in the factory area have a large amount of usage and are also standard low-pressure flanges in the chemical plant area. Mainly used for chemical circulating water pipelines, equipment cooling water, desalinated water, factory exhaust gas ventilation pipelines, workshop sewage discharge, non hazardous neutral material transportation pipelines, compatible with HG/T20592 chemical special plate flat welding flanges, only used for atmospheric pressure, low pressure, non-toxic, and non permeable medium pipelines. The use of high-risk process pipelines is prohibited.

3. HVAC+Building Fire Protection Industry

Industrial parks, commercial buildings, factory HVAC systems, chilled water, cooling water, fresh air ventilation pipelines, indoor and outdoor fire water supply pipelines, and large-scale use of PN16 plate flat welding flanges. The medium temperature is stable, the pressure is constant, and there is no severe vibration. Paired with ordinary rubber gaskets and PTFE gaskets, it can meet the sealing requirements, while balancing procurement costs and installation efficiency. It is a standard flange in the HVAC and fire protection industry.

4. Thermal power environmental protection water treatment industry

火电、热电厂区补水管道、脱硫脱硝灰水管道、除尘风管；污水处理厂生化池管路、超滤反渗透常压管路、中水回用管道，均批量使用板式平焊法兰。工况低压常温、介质弱腐蚀，选用不锈钢板式平焊法兰即可满足防腐使用需求，替代高价带颈对焊法兰，有效控制工程造价。

二、板式平焊法兰通用适配工况（选型标准）

适配标准：HG/T20592化工板式平焊法兰、GB/T9119国标板式平焊法兰

适配压力：仅限PN6、PN10、PN16，最高不超过PN25

适配温度：-20℃~150℃常温工况，超温禁用

适配介质：清水、污水、空气、循环水、中性弱腐蚀介质、无毒无味非危化介质

适配环境：管道振动小、压力平稳、无负压真空、无冲击压力管路

三、板式平焊法兰绝对禁用行业工况（工程红线）

1、化工工艺管线：甲醇、液氯、芳烃、易燃易爆、有毒渗透性介质管道，禁止使用PL板式平焊法兰，必须选用WN带颈对焊法兰；

2、高温高压管路：150℃以上蒸汽、导热油、高压工艺气、临氢管道严禁使用；

3、动力设备出口：水泵、压缩机、风机进出口震动管路，禁止选用；

4、设备管口对接：反应釜、储罐、塔器压力容器管口，需用NB/T47020压力容器法兰，不可混用板式平焊管道法兰；

5、真空管路、高密封防爆管路，全程禁用板式平焊法兰。

四、为什么低压行业优先选板式平焊法兰？

1、性价比高：价格仅为带颈对焊法兰50%-60%，大批量工程大幅降低采购成本；

2、施工简单：管道插接双面角焊即可，无需坡口加工、无需无损探伤，缩短施工工期；

3、通用性强：RF突面密封为主，垫片选配简单，国标化工标准可互通互换，备货便捷。

文章总结

板式平焊法兰使用最多三大行业：市政给排水＞化工公用工程＞暖通消防环保，核心定位就是：低压、常温、非危化、小震动、成本可控管网。只要避开高温、高压、有毒易燃易爆、压力容器对接工况，均可放心选用PL板式平焊法兰。