What does EN1092-1 cover?

EN1092-1 covers circular steel flanges, and it replaced the old British standard BS4504, so you’ll still see BS4504 on older drawings and pipework.

It also sets out the flange type, such as slip-on or weld neck, and the face, such as flat or raised. Both appear in our product names. Most European pipework follows this standard.

What do PN16, PN10 and DN mean?

DN is the nominal diameter, the European way of sizing pipe and flanges. PN is the nominal pressure rating, so PN16 is a higher rating than PN10 and PN40 is higher again.

PN is a rating designation rather than a working pressure. What a flange can take depends on the material and the temperature, so tell us the duty and we’ll help you choose.

How do you read an EN1092-1 flange description?

Take a name such as DN150 EN1092-1 PN16/13B RF. It breaks down into four parts:

1. DN150 is the size.

2. PN16 is the pressure rating.

3. 13 is the flange type, which is a hubbed threaded flange.

4. B is the face, which means a raised face. Our names also describe this as RF.

The type numbers you’ll see most often are:

01 plate flange for welding, which is the slip-on type

02 loose plate flange, used as a lap joint flange

05 blank flange, which is the blind type

11 weld neck flange

13 hubbed threaded flange

For PN2.5 up to PN40, the standard calls the raised face B1.

What are the common ordering mistakes?

The first mistake is treating PN as a working pressure. PN is a rating, not the pressure the flange will take in use, because that depends on the material and the temperature.

The second is mixing EN1092-1 with ANSI B16.5. EN1092-1 flanges as they are sized by DN and PN, while ANSI B16.5 flanges use NPS and class. The drilling is different, so the two won’t fit together.

The third is overlooking the face. A flange needs to suit the face of the flange it’s joining, so check the facing letter in the name, such as B for a raised face.

What should you tell us when you enquire?

The quickest way to get the right EN1092-1 flange is to start with the DN size and the PN rating. Please tell us:

1. The DN size and the PN rating, because together they fix the dimensions and the drilling.

2. The flange type, using the type number if you have it, for example 01 for slip-on or 11 for weld neck.

3. The face, which is raised face for most of our range.

4. The grade, either 304 or 316.

5. How many you need.

If you’re replacing a flange, the markings on it will usually tell you most of this. We’re happy to help you read them if you send us a photo.

Frequently asked questions

What is the difference between EN1092-1 and BS4504?

EN1092-1 replaced the old British standard BS4504. You’ll still see BS4504 on older drawings and pipework, but the current standard is BS EN 1092-1.

What do PN and DN mean on a flange?

DN is the nominal diameter, which is the European way of sizing pipe and flanges. PN is the nominal pressure rating, so PN16 is a higher rating than PN10. PN is a designation rather than a working pressure, because that depends on the material and temperature.

What does PN16/13B mean in a flange name?

PN16 is the pressure rating. The 13 is the flange type, which is a hubbed threaded flange, and the letter B means a raised face.

Which PN ratings do you hold?

We hold EN1092-1 flanges in PN6, PN10, PN16, PN25 and PN40 ratings, in slip-on, blind, weld neck and threaded form.

Contact Anglo Stainless for more information

To talk through the right rating and type for your system, contact us and speak to a member of our team. You can also request our brochure using the form below.