Incompatible materials

Transition Joints. Use of explosion-clad transition joints avoids the limitations involved in joining two incompatible materials by bolting or riveting. Many transition joints can be cut from a single large-area flat-plate clad and deflvered to limit the temperature at the bond interface so as to avoid undesirable diffusion. Conventional welding practices may be used for both similar metal welds. 

If galvanically incompatible materials are to be used, design the active materigd component so that easy replacement is possible, or allow for anticipated corrosion by appropriately increasing its thickness. 

Isolate process from sources of incompatible material... 

Physically separate points of connection of incompatible materials... 

Shared vent systems, utility systems, or equipment may result in incompatible materials coming together. 

Possibility of combining incompatible materials in drainage and dikes. 

Shared transfer Avoid the use of incompatible materials in systems. shared transfer systems Ensure cleaning procedures are followed Avoid pockets in lines Install dedicated transfer system API RP 750 Kletz 1991 Lees 1996 NFPA-91... 

Clean and inspect equipment after each change Segregate incompatible materials Label material, lines, pumps and valves Use double check system Check labels against batch sheets Use procedures and training Set valves to correct flow path... 

Segregate incompatible materials Clean and inspect equipment after each batch Use procedures and training... 

Label containers according to hazard, precautions, first aid Segregate incompatible materials Maintain good housekeeping... 

Procedures for ensuring Identification of all materials Segregation of incompatible materials Good housekeeping... 

Keep away from. . . (incompatible materials to be indicated by the manufacturer)... 

Hypergolic A hypergolic mixture ignites upon contact of the components without any external source of ignition (heat or flame). The only field, in which this is a desirable event, is in rocket fuel research. Accidental mixing of incompatible materials can lead to a fire or explosion. Here is one example provided by the staff at ILPI of what can happen, when incompatibles are mixed. Always read the labels on your bottles (don t assume a chemical s identity by the shape, size, or color of the bottle), and know what materials are incompatible with the chemicals that you are using. 

Use materials of construction that enhance inherently safer operations. Corrosion leads to leaks incompatible materials can lead to unwanted reactions. 

Avoid incompatible materials that could come into contact in abnormal conditions. 

Adsorbers, distillation colunuis, and packed lowers are more complicated vessels and as a result, the potential exists for more serious hazards. These vessels are subject to tlie same potential haz. uds discussed previously in relation to leaks, corrosion, and stress. However, llicse separation columns contain a wide variety of internals or separation devices. Adsorbers or strippers usually contain packing, packing supports, liquid distributors, hold-down plates, and weirs. Depending on tlie physical and chemical properties of the fluids being passed tlirough tlie tower, potential liazards may result if incompatible materials are used for llie internals. Reactivity with llie metals used may cause undesirable reactions, which may lead to elevated temperatures and pressures and, ullinialely, to vessel rupture. Distillation columns may contain internals such as sieve trays, bubble caps, and valve plates, wliicli are also in conlacl with tlie... 

Protective measures against bimetallic corrosion should ideally start before the particular installation or equipment is built . Reference should be made to tables showing compatibility of metals, alloys and non-metallic materials (5 Table 1.25) and to the literature. However, it must be emphasised that the environment obviously plays a most important role in bimetallic corrosion, and that there are a number of situations in which apparently incompatible materials in contact can be used without adverse effects. 

Before applying a protective coating it is essential to ensure that the surface is free from rust, millscale, moisture, loose dust, or any other incompatible material which might prevent the electrically non-conducting coating from bonding properly with the metal surface or which might produce defects in the continuous film. 

Keep In a cool well-ventilated place away from [incompatible materials to be Indicated by... 

Controls for the safe transfer of chemicals between ship and shore will vary in detail. The escape of dust and vapour should be minimized when loading and unloading of bulk liquids or solids and persons should not be at risk. Precautions to avoid contact with water are needed when transferring water-incompatible materials (page 229). Precautions for handling explosives include ... 

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