This publication addresses the risks to persons in occupied buildings within ASU and HYCO facility boundaries associated with pressure energy. Pressure energy can be generated from ignition of flammable material that has been released into congested or confined area and the sudden failure of pressure vessels. Section 6.4 provides criteria for the exclusion of specific pressure vessel mechanical failures from consideration.

This publication is intended to provide guidance on determining the risk to persons in:

• new permanent or portable occupied buildings on ASU and HYCO facilities;
• existing occupied buildings from a new ASU plant, HYCO plant, or major modification added to an existing facility;
• an occupied building from a relocated ASU plant, HYCO plant; and
• a relocated occupied building.

It is also intended to provide guidance on how to address hazards from neighboring facilities during the design of new ASU and HYCO plants. The provisions of this publication are effective as soon as hazardous materials are introduced into the ASU or HYCO facility.

The scope of this publication is not intended to cover the following:

• Existing buildings in existing ASU and HYCO plants;
• Occupied buildings beyond the ASU or HYCO facility boundary, as this publication is specific to on-site impacts within ASU and HYCO facilities. CCPS Guidelines for Facility Siting and Layout, the Seveso III Directive, and other sources provide general guidance on this topic;
• The location and design of occupied buildings as related to exposures from toxic gas releases. API RP 752, Management of Hazards Associated with Location of Process Plant Buildings, API RP 753, Management of Hazards Associated with Location of Process Plant Portable Buildings, and the CIA document Guidance for the Location and Design of Occupied Buildings on Chemical Manufacturing Sites provide guidance on mitigation of hazards related to a toxic release;
• The location of oxygen and inert gas vents relative to the location of buildings. EIGA Doc 154, Safe Location of Oxygen and Inert Gas Vents provides guidance on the safe location of oxygen and inert gas vents; and
• Cryogenic spills from air separation facility equipment. Many CGA and EIGA publications provide guidance on control of cryogenic spill hazards; see Section 10 for additional references.

For industrial gas facilities not included in the scope of this standard, see NFPA 55, Compressed Gases and Cryogenic Fluids Code or other equivalent regional standards for siting considerations.