API STD 2015:2001 pdf download

API STD 2015:2001 pdf download.Requirements for Safe Entry and Cleaning of Petroleum Storage Tanks.
3.2.10 degassing: The process of collecting, oxidizing or treating vapors and gases expelled from a tank or vessel so as to prevent or reduce the amount of organic volatile compounds released into the atmosphere during vapor and gas freeing operations.
3.2.11 double block and bleed: The positive closure of a line or pipe by closing and locking or tagging two in-line valves and by opening and locking or tagging a drain or vent valve in the line or pipe between the two closed valves.
Note: Employers may evaluate and designate a single valve that uses two sealing surfaces with a drain orifice beween them as satisfying double block and bleed requirements.
3.2.12 electrical division classification of hazardous (classified) locations: The division classification system is used to designate locations where fire or explosion hazards may exist due to the potential for the presence of flammable gases, vapors or liquids.
Note: These classifications are identical to those defined by NFPA 70, The National Electric Code.
3.2.12.1 Class I, Division 1: A location wherein any one of the following conditions applies:
• Ignitable concentrations of flammable gases or vapors exist under normal operating conditions.
• Ignitable concentrations of flammable gases or vapors may exist frequently because of repair or maintenance operations or because of leakage.
• Ignitable concentrations of flammable gases or vapors might he released by breakdown or faulty operation of equipment or processes that might cause electrical equipment to simultaneously fail in such a manner as to become a source of ignition.
3.2.12.2 Group D location: A division classified location wherein any of the following conditions apply:
• A specific level of protection that is required for flammable and combustible liquid vapor or gas that may burn or explode when mixed with air and exposed to a specific ignition source.
3.2.12.3 Group A, B, and C locations: Some petrochemical products require higher levels of protection than Group D, including, hut not limited to, acetylene (Group A), hydrogen (Group B) or ethylene (Group C) (see NFPA 70, Article 500, “Hazardous Classified Locations,” and NFPA 30, “Flammable and Combustible Liquids,” for additional information).
3.2.13 electrical zone classification of hazardous (classified) locations: The zone classification system is an alternate system (to division classification) for locations where fire or explosion hazards may exist due to flammable gases, vapors, or liquids.
3.2.17 engulfment: The surrounding and effective entrapment of an entrant by a liquid or finely divided (flowable) solid substance that can be aspirated to cause death by filling or plugging the respiratory system or that can exert enough force on the body to cause death by strangulation, constriction or crushing.
3.2.18 entrant: A qualified person who is authorized by the entry supervisor to enter a confined space.
3.2.19 entry: The action by which an entrant passes through an opening into a confined space. Entry includes ensuing work activities in both permit required confined spaces and non-permit confined spaces. and is considered to have occurred as soon as a part of the entrant’s body breaks the plane of an opening into the space.
3.2.20 entry permit (confined space): The written or printed document provided by the employer (owner/operator or contractor) and issued by an entry supervisor that provides the site, potential hazard and work specific information necessary to control and authorize entry into a permit-required confined space including conditions canceling the permit and requirements for safeguarding or returning the space to service following termination of entry.
3.2.21 entry supervisor: The qualified person (employee, foreman, supervisor, crew chief, etc.) designated by the employer (owner/operator and contractor) to be responsible for determining the requirements and whether or not acceptable entry conditions exist at permit required confined spaces and non-permit required confined spaces, where entry is contemplated. Entry supervisors shall authorize entry. oversee entry operations and terminate entry as required by the permit or conditions. An entry supervisor, who is properly qualified, trained and equipped, may serve as an attendant or as an entrant. The duties of entry supervisor may be passed from one entry supervisor to another entry supervisor, during the course of an entry operation.
3.2.22 explosive (flammable) range: The range of concentrations of flammable vapor-in-air, between the lower explosive (flammable) limit and the upper explosive (flammable) limit that will propagate flame if ignited.
3.2.22.1 lower explosive (flammable) limit (LEL):
The minimum concentration (expressed as a volume percentage) of a vapor-in-air below which propagation of flame does not occur on contact with an ignition source; generally considered to be “too lean to burn.”