The many and varied joys of “Class Locations”


Most of the proposed PennEast pipeline route will use substantially lower safety standards than would be required in dense suburban or urban neighborhoods.  Those of us in rural locations will have thinner walls, the pipe will be buried less deeply in the ground, and will have fewer safety inspections than it will in areas of higher population density.


Pipeline safety has become a hot topic around the PennEast pipeline, and people particularly want to know how this thing is proposed to be built, how safe it might be, and what issues might come up if it is built.  And they’re worried – and rightfully so.  There are rumors that different areas get different treatment.  That rural lives and property are considered to be worth less than those in more suburban or urban environments.  That some of the “Best Management Practices”…aren’t.

So now looks like a good time to address those issues.  I’ll be drawing on PennEast’s filings for this information, along with government regulations that mandate certain practices, and what the industry has been doing to change those regulations.

Right off the bat let me tell you this: the rumors you hear are true. If you live in the country, your life, your family’s lives, and your pets and farm animals, your property, your house, your barns, your pools, your ponds and fire pits – they’re all considered to be worth less than those who live in the suburbs or the city. This is because of “Class Locations”.  Read on for what this means for you.


Decades ago some bright Department of Transportation people decided that we needed to regulate the construction of natural gas pipelines.  In their infinite wisdom they decided NOT to make pipelines as safe as possible.  Oh, no.  That would cost pipeline companies a lot of money.  So instead they chose what’s called a risk model that was based on population density near a pipeline.

A risk model outlines potential risks that a potential project can face, and draws lines where it thinks risks are acceptable, and where they are not.  In places where they aren’t, they dial back the parameters until they’ve found what is acceptable.

The definition of “acceptable” is up to the people drawing up the risk model (and those who approve it).

In terms of natural gas pipelines they decided the big issue at hand would be the impact of a pipeline breach near human population centers.  They figured that out in the country, there’d be a low impact, in suburban areas there’d be somewhat more impact, and in urban areas there’d be a very high impact.

“Impact” is not defined in terms of human life, but generally in terms of economic impact – the damage the accident incurs, and the amount of money it takes to fix it.  As a piece of this individual humans get a (somewhat arbitrary) economic number assigned to them.

They then modeled what “population centers” looked like.  They decided (again, in their infinite wisdom) that there were 4 classes of population they would look at:

Class 1 – Underwater, or with 10 or fewer inhabited dwellings within 220 yards of the pipeline centerline over a 1 mile length.

Class 2 – 11 to 46 inhabited dwellings within 220 yards of the pipeline centerline over a 1 mile length.

Class 3 – 47+ buildings within 220 yards of the pipeline centerline over a 1 mile length, or an outdoor space or building where 20+ people will gather.

Class 4 – A location where they are many 4 story+ tall buildings (e.g. urban).

High Consequence Area – A location that is deemed especially sensitive or important, or where evacuation may be difficult (a school, a busy and often crowded park, a hospital).

In this manner the DOT people modeled population density as it related to natural gas pipelines.  And they decided the more people there were around a pipeline, the safer they would make it.


Your class location has three important impacts on pipeline construction:

  • How thick the pipe is
  • How deeply it is buried
  • How often it is inspected

As you can imagine, class 1 gets the least protections, class 4 gets the most.

Pipeline thickness

Finding out the thickness of your pipe is difficult.  It relies on a number of factors, so it’s hard to find it online.  The exact thickness depends upon the pressure of the pipeline (PennEast is 1480 psi), the width of the pipeline (36″ for PennEast), the safety factor for the class location, and the quality of steel being used.

We know all of those items except of the grade of steel PennEast will be using.  It’s not clear if we’ll get those numbers as they may be considered privileged information to protect critical infrastructure (e.g. they’re afraid of terrorists knowing).

But we do know the other parameters, and the most important is the safety factor.

The safety factor is somewhat mis-named.  The number itself is not an indication of the safety factor, but actually is an indication of how close they’re allowed to come to the rated stresses for the type of pipe they’re using.  As an example, a safety factor of 100% would be for a situation where a pipeline would be allowed to run up to 100% of its rated strength (note: this is a made up example, nothing would ever be allowed to run to maximum tolerance with no margin for error).  So even though it’s called a safety factor the actual number indicates how close to the pipeline strength rating you’re allowed to come.

The actual safety factors for pipelines are 72%, 60%, 50%, and 40%.

Note that pipelines operate at a constant pressure across its length, so in reality the safety factors translate into varying pipe widths and/or higher grade pipe.  So if you live on a farm or out in the woods you’ll get a less safe pipe by design then your friends a few miles away who live in a large housing development.

How deeply the pipe is buried

Class location also impacts how deeply the pipe must be buried.  At class 1 locations it can be closer to the surface, at higher locations it must be buried more deeply.  In agricultural areas the pipeline must also be buried more deeply to minimize crop impact, as standard depths are not nearly deep enough.

How often it is inspected

Finally class location defines how often the company is required to inspect the pipeline.  Most pipeline companies trumpet the fact that they have electronic monitoring systems that operate 24/7 so the on-site pipeline walks are unimportant.  This is not actually the case – regular pipeline walks are often neglected but are actually vital as automated equipment can fail, give false positives, give false negatives, or simply be ignored.

Class 1 Location

At this location the pipeline will be allowed to operate up to 72% of the structural stresses allowable, which translates into a thinner pipe and/or lower grade steel.

The pipeline must be buried so it’s top is only 30″ from the surface of the ground – except in areas with hard ground/bedrock.  In those areas it only needs to be 18″ from the surface.

Class 1 locations require the least amount of physical on-the-ground inspections.

Class 2 Location

At this location the pipeline will be allowed to operate at 60% of its structural stresses, so in practice it’s the second thinnest steel.

The pipeline must be buried so its top is 36″ from the surface of the ground, 24″ in areas with hard ground/bedrock.

They require more physical inspections than class 1.

Class 3 Location

At this location the pipeline will be allowed to operate at 50% of its structural stresses, so it’s thicker steel than in class 1 or 2.

Depth requirements are same as for class 2 – 36 ” or 24″ in hard rock/bedrock.

Physical inspection requirements are the same as class 2.

Class 4 Location

At this location the pipeline will be allowed to operate at 40% of its structural stresses, so it’s the thickest steel.

Depth requirements are same as for class 2 – 36 ” or 24″ in hard rock/bedrock.

Physical inspection requirements are the same as class 2.

High Consequence Area

These areas would have increased monitoring and integrity checks over other areas,and include places like schools, beaches, parks, etc where many people will gather/inhabit.


PennEast has indicated in their federal filings that they will upgrade the to a minimum of class 2 safety factor for the length of the pipeline, even for class 1 areas.  So the pipeline will be operating at 60% of maximum allowable stresses in those areas.  Class 3 areas will still get the thicker pipe and 50% maximum allowable stresses.

The “class 2 upgrade” only applies to the pipe thickness. They will still be burying the pipe more shallowly in class 1 locations.

Incredibly, PennEast has identified ZERO High Consequence Areas, even though there are many that have been identified by myself and others (examples: the strip mall in PA near route 33, the private Christian school in the same area, etc).

Published by

Mike Spille

I'm a thinker, an analyzer, a synthesizer. Maybe not in that order. I live in West Amwell NJ with my wife Kristina, our two kids Day and Z, our two dogs Fern and Cinna, and three cats Ponce de Leon, Oliver, and Doolittle.

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