pressure equipment ped category calculator

What this PED calculator does

This tool gives a fast, practical estimate of pressure equipment classification according to the Pressure Equipment Directive (PED) 2014/68/EU framework. It is designed for early project scoping, quotation work, and design reviews when you need a quick category indication before full code assessment.

Inputs used

• Equipment type: Vessel or piping
• Fluid group: Group 1 (hazardous) or Group 2 (non-hazardous)
• Fluid state: Gas/vapor or liquid
• PS: Maximum allowable pressure in bar
• Size parameter: Volume (V) for vessels or DN for piping

How the estimate is calculated

Step 1: Basic PED scope check

If PS ≤ 0.5 bar, the equipment is typically outside PED scope. This calculator reports that immediately.

Step 2: Calculate governing index

• Vessels: index = PS × V
• Piping: index = PS × DN

Step 3: Map index to estimated category

Depending on fluid group and fluid state, the index is compared with threshold bands and classified into SEP, I, II, III, or IV.

Thresholds used by this estimator

The values below are simplified screening thresholds to support quick engineering decisions.

Vessels (using PS × V)

Fluid	SEP	I	II	III	IV
Gas, Group 1	≤ 50	50–200	200–1000	1000–3000	> 3000
Gas, Group 2	≤ 200	200–1000	1000–5000	5000–10000	> 10000
Liquid, Group 1	≤ 200	200–1000	1000–5000	5000–10000	> 10000
Liquid, Group 2	≤ 1000	1000–5000	5000–10000	10000–20000	> 20000

Piping (using PS × DN)

Fluid	SEP	I	II	III	IV
Gas, Group 1	≤ 100	100–350	350–1000	1000–2500	> 2500
Gas, Group 2	≤ 200	200–1000	1000–3500	3500–7000	> 7000
Liquid, Group 1	≤ 200	200–1000	1000–3500	3500–7000	> 7000
Liquid, Group 2	≤ 500	500–2000	2000–7000	7000–14000	> 14000

Why category matters

PED category affects the conformity route, notified body involvement, technical documentation effort, and CE marking process. As category increases, the compliance pathway typically becomes more rigorous.

• SEP: Sound engineering practice (usually no CE mark under PED for that item category)
• Category I: Lower-risk CE conformity route
• Category II–IV: Increasing compliance depth and third-party involvement

Important engineering note

Practical workflow after getting an estimate

1. Run this estimate during concept design.
2. Confirm fluid classification and design data (PS, TS, volume, DN).
3. Perform full PED table check for final category.
4. Select the conformity assessment module with your compliance team/notified body.
5. Compile technical file and marking documentation.