3 explanation of the fuel gas code tables for natural gas 2018 code book
People & Blogs
Introduction
In this article, we delve into the intricacies of the natural gas tables laid out in the Fuel Gas Code. Specifically, we will focus on item number three, which provides a comprehensive explanation of these tables. The relevant tables are identified within the sections 6.2.1 A through 6.2.1 X.
Overview of the Tables
Table Identification
The first point of reference is Table 6.2.1 A, which details various piping materials used for natural gas systems. These materials are crucial for understanding which type of piping is appropriate for different applications.
Table 6.2.1 X represents polyethylene plastic tubing, compatible with utilities and ideal for running gas pipelines to structures like garages.
Gas Type and Pressure
It is imperative to recognize that all natural gas tables include an item number "2". This standardization means that you must be vigilant in ensuring you are using the correct gas type, especially regarding gas pressure.
When sizing your gas line, the inlet pressure from the point of delivery—typically after the regulator—must be verified. Proper pressure drop calculations are also essential; it is important to check the allowable pressure drop within your gas distribution system.
Commonly Used Tables
One of the tables I frequently refer to is Table 6.2.1 B, which outlines a 0.5-inch water column pressure drop—often the most commonly used for schedule 40 systems.
For instance, if your system operates at an inlet pressure of less than 2 psi, you are probably working with a 7-inch water column gas supply pressure.
Pipe Specifications
The tables clearly specify the nominal size for pipes. For example, a half-inch pipe nominally has an internal diameter of around 0.622 inches, while a three-quarter inch pipe measures about 0.824 inches.
They also account for lengths in feet, ranging from 10 feet up to over 2000 feet, allowing flexibility in various applications.
Pressure Drop Calculation
Understanding gas flow involves calculating the total BTUs required for your system. Obtaining the right cubic feet per hour of gas is crucial when determining line sizes.
To illustrate, if you have a 50,000 BTU appliance with an efficiency of 1000 BTUs per cubic foot, the gas flow requirement would be 50 cubic feet per hour. As appliances feed into a main line, it's important to track cumulative demands to ensure adequate gas supply throughout the system.
Material Types
Different materials also influence sizing and pressure drop calculations. For instance, gas distribution might utilize not just schedule 40 pipe but could also include copper tubing (types K and L) and specific stainless-steel tubing.
The tables also include polyethylene plastic tubing, usually designated by its distinctive yellow exterior, optimized for underground installations.
Summary
The fuel gas code tables serve as critical guides for anyone involved in the natural gas application process, from sizing to material selection. This article has provided an overview of how to navigate these tables, the importance of input parameters like gas type and pressure, and common practices for managing gas distribution in residential and commercial spaces.
Keywords
- Natural Gas
- Fuel Gas Code
- Pressure Drop
- Piping Materials
- BTUs
- Cubic Feet
- Sizing Tables
- Polyethylene Tubing
- Schedule 40 Pipe
- Copper Tubing
FAQ
What are Fuel Gas Code Tables?
The Fuel Gas Code Tables are standardized guides used to determine the appropriate sizing, materials, and calculations needed for natural gas systems.
What is the importance of inlet pressure?
Inlet pressure is critical as it affects the pressure drop calculations and the overall efficiency of a natural gas system.
What is a common pressure drop used in gas systems?
A commonly used pressure drop in gas systems is 0.5 inches of water column, as specified in Table 6.2.1 B.
How do you calculate gas flow in cubic feet for appliances?
To calculate gas flow, divide the appliance's total BTU requirement by the BTUs per cubic foot of gas (e.g., 50,000 BTUs / 1000 BTUs per cubic foot equals 50 cubic feet per hour).
What materials are included in the gas tables?
The gas tables include a variety of materials such as schedule 40 steel pipes, copper tubing (types K and L), stainless steel tubing, and polyethylene tubing for underground applications.