Plate vs. Forged Flange Selection Guide

Answer 5 questions about your application to get a recommendation. Plate flanges (EN 1092-1 Type 01 / ASME slip-on) are not a compromise option — they are the specified choice for many industrial applications. This guide identifies when each type is the correct engineering selection.

Question 1 of 5

What is the operating pressure class of your piping system?

≤ PN16 / Class 150 (≤16 bar / ≤19.6 bar)General utility, water treatment, HVAC, low-pressure process headers

PN16–PN40 / Class 150–300 (16–40 bar range)Medium-pressure process piping, chemical processing, oil and gas utility service

PN40+ / Class 600 and above (>40 bar)High-pressure process, wellhead service, steam above Class 300 conditions

Question 2 of 5

What is the operating temperature range?

Ambient to 200°C (up to ~400°F)Water, cooling systems, ambient-temperature chemical service

200–400°C (400–750°F)Steam service, thermal oil, elevated-temperature process

Above 400°C (above 750°F)High-temperature steam, power generation, furnace services

Question 3 of 5

Is the piping system subject to cyclic loading, vibration, or fatigue conditions?

No — static service, steady-state flowUtility headers, fixed plant, non-vibrating applications

Moderate — some vibration, thermal cyclingPumped systems, process lines with temperature swings, outdoor installations

Severe — offshore, compressor stations, fatigue-criticalOffshore topsides, compressor suction/discharge, wave-loaded structures

Question 4 of 5

What is the primary application / service category?

Water / AWWA / Building servicesWaterworks (AWWA C207), HVAC, fire protection, municipal distribution

General industrial / chemical processingPlant utility headers, chemical process lines, food and beverage, pharmaceutical

Oil and gas upstream, offshore, or power generationAPI 6A/6D applications, wellhead, offshore, ASME B31.3 high-pressure process

Question 5 of 5

Does the piping specification or project QA plan reference API, ASME pressure vessel code, or fatigue qualification?

No — EN 1092-1 or general ASME B16.5 specification onlyStandard industrial or utility piping, no API or ASME vessel code requirement

ASME B31.3 process piping (stress analysis required)Formal stress analysis to B31.3; flexibility factor calculations may apply

API 6A, API 6D, ASME pressure vessel code, or fatigue specWellhead service, pressure vessel nozzles, API-coded equipment

Selection Rationale

Synbase manufactures both plate flanges (EN 1092-1 Type 01 / ASME slip-on) and forged flanges (weld neck, blind, socket weld). Both types can be supplied from the same manufacturer with unified MTR documentation — simplifying TPI inspection and reducing supplier qualification overhead.

Request a Quote — 24-Hour Response