What is the difference between B36.10 and B36.19?

By Katherine Grace & Jay Walton

Simply put, B36.10 and B36.19 refer to different engineering standards regarding steel piping systems.  

B36.10 relates to the standards of wrought steel and carbon steel piping system components. 

B36.19 relates to Stainless steel piping system components. 

But what does this mean, and which one should you choose? Keep reading for an exploration from theory to the purchase and installation of components of piping systems that abide by these internationally employed standards. 

The integrity of a piping system depends on the considerations and principles used in design, construction, and maintenance of the system. Piping systems are made of components such as Pipe, Flanges, supports, gaskets, bolts, valves, strainers, flexible and expansion joints. The components can be made in a variety of materials, in different types and sizes. These systems are often manufactured to the particular standards – but where do they come from? 

When coming across the terms B36.10 and B36.19, they are usually preceded by either ASME or ANSI. These refer to the organisations that have developed and implement these standards: 

ASME - American Society of Mechanical Engineers

• A 120,000-member professional organisation focused on technical, educational and research issues of the engineering and technology community.  

• ASME sets internationally recognised industrial and manufacturing codes and standards that enhance public safety. 

ANSI – The American National Standards Institute

• A private, non-profit organisation that administers and coordinates the U.S. voluntary standardisation and conformity assessment system. 

• ANSI provides a forum for development of American national standards from organisations such as ASME, and more. 

 As ANSI is informed by ASME, these two terms can be used interchangeably. However, different organisations will often have different standards, so research is always required before purchase. 

Engineering, of course, comprises an enormous scope of systems and projects. That’s where the specific codes B36.10 and B36.19 come in. 

As outlined, B36.10 relates to the standards of wrought steel and carbon steel piping system components, and B36.19 relates to Stainless steel piping system components. 

At certain sizes, B36.19 differs in wall thickness and weight from B36.10 and hence it matters if you specify Pipe and piping system components to B36.10 or B36.19. This difference can be found in the schedule of the Pipe and its corresponding measurements.

Schedules

Steel Pipe schedules are used to describe the wall thickness for Pipe. A Pipe schedule is calculated based on the design formula for wall thickness, given the design pressure and allowable stress. As the schedule number increases, the wall thickness of the Pipe increases. The schedule number of a pipe therefore defines the internal diameter.   

Stirlings services a large variety of different industries and as such carry a large variety of schedules. 

High Pressure applications such as the Oil & Gas industry often require heavier and thicker pipelines like Schedule 80S & Schedule 160S, whereas low pressure applications like the HVAC industry and the Water Treatment industry use very thin wall light pipes such as Schedule 5S and Schedule 10S. 

See below to outline examples of the similarities & differences between B36.10 and B36.19 schedules.   

Standard Weight (STD) / True Schedule 40 / Schedule 40S 

• ¼” (6nb) to 10” (250nb) – The wall thicknesses for B36.10 and B36.19 are identical. 

• 12” (300nb) - Standard Weight STD & Schedule 40S remain the same (9.53mm) but what we call “True Schedule 40” becomes thicker at 10.31mm.  

• 14” (350nb) and above - B36.19 no longer covers these sizes and larger items are usually ordered to the size standards of B36.10M. In these B36.10M sizes, STD remains 9.53mm all the way through to 48” (1200nb) whereas True Schedule 40 is thicker and changes for each size. 

• There are a few rare crossovers, i.e 16” (400nb) True Schedule 40 is the same as Extra Strong (XS), being 12.70mm. 

XS (B36.10M) / Schedule 80S (B36.19) / True Schedule 80 (B36.10M)   

• ¼” (6nb) to 8” (200nb) - The wall thicknesses for B36.10 and B36.19 are identical. 

• XS & Schedule 80S remain the same through to 12” (300nb) where B36.19 no longer covers sizes larger than this. 

• 10” (250nb) and above - XS and True Schedule 80 separate, XS remains the same (12.70mm) and True Schedule 80 gets thicker with each size increase. 

• 14” (350nb) and above - Stainless steel items are generally noted and made to the schedule system outlined in B36.10M. 

Please note that there are several Schedules in between, beginning with the very thin and light Schedule 5s (B36.19) through to the heavy duty XXS (B36.10M). 

There is no need to remember all these rules by heart! Click here for our Pipe Spec Sheet which outlines all these schedules and the specific thickness for each size and specification. 

A rhyme for your time

To find the type of Pipe you like, here’s our Spec Sheet, give it a swipe!