Piping systems, design reactions

Thermal expansion is a major factor to be considered in the design of piping systems. The reaction load due to pressure drop will normally be negligible. The dead-weight loads can be carried by properly designed supports. 

Pipe supports and restraints are not considered in the flexibility calculation. It is assumed that the supports which have not been considered in the analysis should be located and designed so as not to interfere with the flexibility of the system. The reactions computed by this method shall not exceed the limits which the attached equipment can safely sustain. Application of such equipment as pumps, turbines and similar strain sensitive machines should receive the manufacturer s approval and the piping system design should be flexible enough to comply with their recommendations. 

Reaction forces and moments to be used in design of restraints and supports for a piping system, and in evaluating the effects of piping displacements on connected equipment, shall be based on the reaction range,... 

Qualification of equipment—The qualification of BPC process equipment including reaction vessels, receivers, crystallizers, centrifuges, dryers, filters, distillation columns, solvent distribution systems, etc. is a well-defined activity. While this equipment is somewhat different in design and operating features, than the dosage form equipment that has been the subject of the majority of papers on the subject, the same general principles apply. Reaction vessels, receivers, and crystallizers differ only minimally from formulation and water for injection tanks. Some BPC dryers are identical to those utilized in tablet departments. Solvent distribution systems are piping systems and may resemble WFI distribution systems. Some pieces of equipment such as distillation columns... 

Containers of pyrophoric gases must be kept away from heat, sparks, and open flames in a well-ventilated area. Spark-resistant tools should be used. Use pyrophoric gases only in a closed system designed to withstand the pressure involved. All equipment should be evacuated or purged with inert gas prior to opening the cylinder valve. Use a check valve or back-flow protection device in any line or piping from the container to prevent reverse flow and potential reaction, which could cause a container failure. 

Reactions involving a solvent under reflux require the use of modified commercial microwave ovens. In these modified systems the oven is perforated on the top to accommodate a reflux condenser and a 10 cm pipe is used to avoid microwave leakage the turnable dish is replaced by a magnetic stirrer or by monomode reactors especially designed for chemical synthesis [15]. 

DIERS[1) presented a series of design charts, based on the Omega method, which can be used to evaluate the thrust force. These charts do not include the dynamic load factor, FD. If a load is suddenly applied, as will be the case following operation of a relief system, the piping will. experience a dynamic load of approximately twice the applied load. It is therefore usual to use a dynamic load factor of 2 in equation (12.1). Leung121 also discusses the use of the Omega method to calculate reaction forces. 

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