25.1 INTRODUCTION

Specialty gases are commonly defined as the process gases supplied from cylinders. This is in contrast to bulk gases such as nitrogen, oxygen, argon, and hydrogen that are provided via pipeline, generated on-site, or delivered in bulk and supplied from cryogenic storage tanks. As is the case with many critical process support systems, the purpose of specialty gas systems is the safe, reliable, consistent, and cost-effective supply of the required quality product to the manufacturing processes. Implementation of a successful specialty gas supply involves the understanding and execution of several interdependent activities. Figure 25.1 illustrates some of the basic implementation elements. While it may be obvious that the process needs (e.g., moisture, particles) directly influence the cylinder gas specifications, other decisions will also influence the product purity (e.g., gas cabinet design filtration and purification, cylinder change procedures, tubing specification, system commissioning process). The specialty gas supply design will also be impacted by the interactions and trade-offs among the project budget, distribution concepts (e.g., coaxial versus single-walled tubing), code requirements, industry practices, and site preferences. This chapter looks at the elements shown in Fig. 25.1, beginning with the identification of the process requirements and cylinder gases specifications. The following sections provide an...