# Interstate natural gas pipelines & valves

• rollingstein
In summary, the conversation discusses the frequency of shutoff valves on natural gas pipelines and the time it takes for a pipeline to burn out after a valve is shut off. The estimated distance between shutoff valves is ~30 miles and the burn time for a 5 mile stretch of 24 inch pipeline is 10 minutes. It is also noted that fatalities and injuries typically occur within the first 3 minutes of an incident. The regulations require shutoff valves every 8 miles for some classes of pipelines, with 'class' referring to the number of inhabited buildings within a certain distance. Remote controlled valves are technically feasible but do not have any economic benefit.

#### rollingstein

Gold Member
Often there's these stories on TV about someone accidentally damaging a large diameter natural gas pipeline while digging a ditch etc. and then a huge raging fire.

What I'm wondering about is how frequently are shutoff valves installed on these lines. My intuition says ~30 miles apart at most. If so, how long does 30 miles worth of piped gas take to burn itself out. I'm just trying to get a rough estimate here.

In a flowing interstate pipe I think gas velocity is somewhere about 20 m/sec? Though not sure how to estimate the burn time after the valve is shut off.

This http://www.phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/rcv_rpt.fnl.pdf page 6 gives "10 minutes for a 5 mile stretch of 24 inch pipeline if the failure is near one end".

Page 15 makes the comment that "of 81 incidents studied, virtually all fatalities and injuries occurred within the first 3 minutes".

Page 16 gives a requirement of shutoff valves every 8 miles for some class of pipeline (I've no idea what the jargon means).

Another consideration is the length of time it takes to close any shutoff valves - estimated at 10 minutes for remote controlled valves and 30 to 40 minutes for manual valves. The general conclusion seems to be that RC values were technically feasible but don't have any economic benefit.

The term 'class' refers to the number of inhabited buildings within a certain distance of a gas pipeline. A Class 1 location is offshore, and presumably there are no inhabited buildings nearby. The other Class designations are defined in the Code of Federal Regulations, 49 CFR 192.5.

## 1. What is an interstate natural gas pipeline?

An interstate natural gas pipeline is a network of pipelines that transport natural gas across state lines. These pipelines are typically large in diameter and can span hundreds or even thousands of miles, connecting natural gas production areas to distribution points.

## 2. How do interstate natural gas pipelines work?

Interstate natural gas pipelines work by using compressors to push gas through the pipeline at high pressures. The gas is then regulated and monitored by valves along the pipeline to maintain pressure and ensure safe and efficient transportation. The gas is delivered to various distribution points along the pipeline for use by consumers.

## 3. What are the benefits of using interstate natural gas pipelines?

Interstate natural gas pipelines provide numerous benefits, including reliable and efficient transportation of natural gas to areas of high demand, reducing the need for trucking or shipping of gas. They also help to maintain a steady supply of natural gas, which is an important source of energy for heating, cooking, and electricity generation.

## 4. What are valves used for in interstate natural gas pipelines?

Valves are used in interstate natural gas pipelines to control the flow of gas, monitor and maintain pressure, and isolate sections of the pipeline for maintenance or in case of emergency. These valves are typically automated and can be remotely controlled for efficient operation.

## 5. How are interstate natural gas pipelines regulated?

Interstate natural gas pipelines are regulated by the Federal Energy Regulatory Commission (FERC) in the United States. FERC oversees the siting, construction, and operation of interstate pipelines, as well as their rates and services. The Pipeline and Hazardous Materials Safety Administration (PHMSA) also regulates the safety and integrity of interstate pipelines.