Hot tapping and Pigging

Yesterday, I had learned about the HOT TAPPING and PIPELINE INSPECTION GAUGE (PIG). This method is used in oil and gas industry and it is definitely under piping work. I will explain a little bit for both methods later. For recap, my previous post is about the barge, davit (crane frame), trencher and trenching method (video). Those were a few things that is related to the offshore work. Now, let us get familiar with another method.

The method is

Hot tapping, or pressure tapping. It is the method of making a connection to existing piping or vessels without the interruption of emptying that section of pipe or vessel. Hot tapping is also the first procedure in line stopping, where a hole saw is used to make an opening in the pipe, so a line plugging head can be inserted. You don't need to be confuse because my video here will explain every things about the process.

(hot tapping video)….

Hot tapping can be performed on pipes carrying natural gas, water, sewage, steam, petroleum products, and chemicals, and on any type of pipe.

Second thing is pigging. A pipeline inspection gauge or pig in the pipeline industry is a tool that is sent down a pipeline and propelled by the pressure of the product in the pipeline itself. There are four main uses for pigs:

1. physical separation between different liquids being transported in pipelines;
2. internal cleaning of pipelines;
3. inspection of the condition of pipeline walls (also known as an Inline Inspection (ILI) tool);
4. Capturing and recording geometric information relating to pipelines (e.g. size, position).

Pig is been made with several of material. One kind pig is a soft, bullet shaped polyurethane

foam plug that is forced through pipelines to separate products to reduce mixing.

There are several types of pigs for cleaning. Some have tungsten

studs or abrasive wire mesh on the outside to cut rust, scale, or paraffin deposits off the inside of the pipe. Others are plain plastic covered polyurethane.

Pigs cannot be used in pipelines that have butterfly valves but it can used in the ball valves. Butterfly valves have a plate inside it that can block the movement of the pig.

Butterfly valve 1

ball valve 1

Inline inspection pigs use various methods for inspecting a pipeline. A sizing pig uses one (or more) notched round metal plates that are used as gauges. The notches allow different parts of the plate to bend when a bore restriction is encountered. More complex systems exist for inspecting various aspects of the pipeline.

Intelligent pigs, also called smart pigs, are used to inspect the pipeline with sensors and record the data for later analysis. These pigs use technologies such as Magnetic flux leakage (MFL) and ultrasonics to inspect the pipeline. Intelligent pigs may also use calipers to measure the inside geometry of the pipeline.

pig inside the pipe

pig receiver

pigging process