Toxic gases can be present in confined spaces due to manufacturing processes using toxic substances, biological breakdown of stored products, and welding activities. Common toxic gases include hydrogen sulfide, solvents like kerosene and gasoline, and carbon monoxide. Hydrogen sulfide occurs naturally but can also result from industrial activities and bacterial breakdown. When working with gas pipelines, materials, equipment, welding, design conditions, stress limits, and expansion/flexibility must be considered to ensure safety.

1. Toxic gases and hazardous piping system

2. Toxic gases Toxic gases can be present in a confined space because the type of manufacturing process uses toxic substances as part of the production process, or biological and chemical "breakdown" of the product being stored in a tank, and from maintenance activities (welding) being performed in the confined space. Hazardous gases: gases that are flammable, toxic, corrosive, pyrophoric or oxidizing are considered hazardous gases.

3. Common types of toxic gases encountered in confined spaces are: Hydrogen Sulfide - "sewer gas" a colorless gas with the odor of rotten eggs. Excessive exposure has been linked to many confined space deaths. Solvents - many solvents, such as kerosene, gasoline, paint strippers, degreasers, etc. are not only flammable, but if inhaled at high concentrations can cause central nervous system (CNS) effects.

4. Carbon monoxide, or CO, is an odorless , colorless gas. It is a product of combustion of organic matter under conditions of restricted oxygen supply, which prevents complete oxidation to carbon dioxide(CO2)

5. What is hydrogen sulfide gas? Hydrogen sulfide gas occurs naturally in crude petroleum, natural gas, volcanic gases and hot springs. It can also result from bacterial breakdown of organic matter and be produced by human and animal wastes. Hydrogen sulfide gas also can result from industrial activities, such as food processing, coke ovens, paper mills, tanneries and petroleum refineries. and sewer gas.

6. Things to consider in gas pipe lines Materials and equipments Welding Design Conditions Allowable Stress Values Limits of Calculated Stresses Due to Sustained Loads and Thermal Expansion Expansion and Flexibility