SPRAY APPLICATION, DIPPING, COATING

70-521 (6)x The interior of any enclosed coating or dipping process. (b) Class I or Class II, Division 2 Locations. The following spaces shall be considered Class I or Class II, Division 2 as applicable. (1)* For open spraying, all space outside of but within 20 feet (6.10 m) horizontally and 10 feet (3.05 m) vertically of the Class I, Division 1 location as defined in Section 516-2(a), and not separated from it by partitions. See Figure 1x on following page. (2)* For spraying operations conducted within a closed top, open face, or front spray booth or room, the space shown in Figure 2, and the space within 3 feet (914 mm) in all directions from openings other than the open face or front. The Class I or Class II, Division 2 location shown in Figure 2 shall extend from the open face or front of the spray booth or room in accordance with the following: a. If the ventilation system is interlocked with the spraying equipment so as to make the spraying equipment inoperable when the ventilation system is not in operation, the space shall extend 5 feet (1.52 m) from the open face or front of the spray booth or room, and as otherwise shown in Figure 2A. b. If the ventilation system is not interlocked with the spraying equipment so as to make the spraying equipment inoperable when the ventilation system is not in operation, the space shall extend 10 feet (3.05 m) from the open face or front of the spray booth or room, and as otherwise shown in Figure 2B. (3)* For spraying operations conducted within an open top spray booth, the space 3 feet (914 mm) vertically above the booth and within 3 feet (914 mm) of other booth openings shall be considered Class I or Class II, Division 2. (4)* For spraying operations confined to an enclosed spray booth or room, the space within 3 feet (914 mm) in all directions from any openings shall be considered Class I or Class II, Division 2 as shown in Figure 3. (5)* For dip tanks and drain boards, the 3-foot (914-mm) space surrounding the Class I, Division 1 location as defined in Section 516-2(a)(4) above and as shown in Figure 4. (6) For dip tanks and drain boards, the space 3 feet (914 mm) above the floor and extending 20 feet (6.1 m) horizontally in all directions from the Class I, Division 1 location. Exception: This space shall not be required to be considered a hazardous (classified) location where the vapor source area is 5 square feet (0.46 sq m) or less, and where the contents of the open tank, trough, or container do not exceed 5 gallons (18.9 L). In addition, the vapor concentration during operation and shutdown periods shall not exceed 25 percent of the lower flammable limit outside the Class I location specified in Section 516-2(a)(4) above. (c)* Enclosed Coating and Dipping Operations. The space adjacent to enclosed coating and dipping operations shall be considered nonclassified. Exception: The space within 3 feet (914 mm) in all directions from any opening in the enclosure shall be classified as Class I, Division 2. 70-522 NATIONAL ELECTRICAL CODE 20' (6 m) Spray area Top (plan) Class I or Class II Div. 1 Class I or Class II Div. 2 Roof 10' (3 m) Spray area Front (elevation) For SI units: one inch = 25.4 millimeters; one foot = 0.3048 meter. Figure 1.x Class I or Class II, Division 2 Location Adjacent to an Unenclosed Spray Operation. ARTICLE 516 - SPRAY APPLICATION, DIPPING, COATING 70-523 3' R (1 m) 5'R (1.5 m) 3' R (1 m) 3' R (1 m) "A" Plan 3' R (1 m) Conveyor 3' R (1 m) opening Open face 5'R (1.5 m) "A" Elevation 3' R (1 m) 10' R (3 m) 3' R (1 m) 3' R (1 m) 5' R (1.5 m) "B" Plan 3' R (1 m) Conveyor 3' R (1 m) opening Open face 10' R (3 m) "B" Elevation For SI units: one inch = 25.4 millimeters; one foot = 0.3048 meter. Figure 2.X Class I or Class II, Division 2 Locations Adjacent to a Closed Top, Open Face or Open Front Spray Booth or Room. 70-524 NATIONAL ELECTRICAL CODE Extent of Class I or Class II Division 2 area 3'R (1 m) 3'R (1 m) Enclosed spray booth or room 3' R (1 m) 3' R Plan view (1 m) 3'R 3' R (1 m) (1 m) 3' R (1 m) Elevation For SI units: one inch = 25.4 millimeters; one foot = 0.3048 meter. Figure 3.x Class I or Class II, Division 2 Location Adjacent to Openings in an Enclosed Spray Booth or Room (d) Adjacent Locations. Adjacent locations that are cut off from the defined Class I or Class II locations by tight partitions without communicating openings, and within which hazardous vapors or combustible powders are not likely to be released, shall be classified as nonhazardous. (e) Nonhazardous Locations. Locations utilizing drying, curing, or fusion apparatus and provided with positive mechanical ventilation adequate to prevent accumulation of flammable concentrations of vapors, and provided with effective interlocks to deenergize all electric equipment (other than equipment approved for Class I locations) in case the ventilating equipment is inoperative, shall be permitted to be classified as nonhazardous where the authority having jurisdiction so judges. (FPN): For further information regarding safeguards, see Ovens and Furnaces, NFPA 86-1990 (ANSI). Point beyond which coated object is no longer a vapor source as defined in Section 516-2(a) (4) Conveyor rail E 11 3 3'(1 m) 15'1.5 m)5'(1.5.m) m) min 5' (1.5 m) 3'(1 m) 3'(1 m) Diptank o 0 o Floor Drainboard 3' (1 m) 3'(1 m) ARTICLE 516 - SPRAY APPLICATION, DIPPING, COATING 5' Pit 5'(1.5 m) 20'(6.1 m) (1.5 m) 20'(6.1 m) 5'(1.5 m) min. The extent of Class I Div. 1 and Class I Div. 2 hazardous locations for open dipping processes. Div. 1 Div. 2 Figure 4.x The Extent of Class I, Division I and Class I, Division 2 Hazardous (Classified) Locations for Open Dipping Processes. 70-525 70-526 NATIONAL ELECTRICAL CODE 516-3. Wiring and Equipment in Class I Locations. (a) Wiring and Equipment - Vapors. All electric wiring and equipment within the Class I location (containing vapor only-not residues) defined in Section 516-2 shall comply with the applicable provisions of Article 501. (b)* Wiring and Equipment - Vapors and Residues. Unless specifically listed for locations containing deposits of dangerous quantities of flammable or combustible vapors, mists, residues, dusts or deposits (as applicable), there shall be no electrical equipment in any spray area as herein defined whereon deposits of combustible residue may readily accumulate, except wiring in rigid metal conduit, intermediate metal conduit, Type MI cable, or in metal boxes or fittings containing no taps, splices or terminal connections. (c) Illumination. Illumination of readily ignitible areas through panels of glass or other transparent or translucent material shall be permitted only if it complies with the following: (1) fixed lighting units are used as the source of illumination; (2) the panel effectively isolates the Class I location from the area in which the lighting unit is located; (3) the lighting unit is approved for its specific location; (4) the panel is of a material or is so protected that breakage will be unlikely; and (5) the arrangement is such that normal accumulations of hazardous residue on the surface of the panel will not be raised to a dangerous temperature by radiation or conduction from the source of illumination. (d)* Portable Equipment. Portable electric lamps or other utilization equipment shall not be used in a spray area during spray operations. Exception No. 1: Where portable electric lamps are required for operations in spaces not readily illuminated by fixed lighting within the spraying area, they shall be of the type approved for Class I, Division 1 locations where readily ignitible residues may be present. Exception No. 2: Where portable electric drying apparatus are used in automobile refinishing spray booths and the following requirements are met: (1) the apparatus and its electrical connections are not located within the spray enclosure during spray operations; (2) electrical equipment within 18 inches (45.7 cm) of the floor is approved for Class I, Division 2 locations; (3) all metallic parts of the drying apparatus are electrically bonded and grounded; and (4) interlocks are provided to prevent the operation of spray equipment while drying apparatus is within the spray enclosure, to allow for a 3-minute purge of the enclosure before energizing the drying apparatus, and to shut off drying apparatus on failure of ventilation system. (e) Electrostatic Equipment. Electrostatic spraying or detearing equipment shall be installed and used only as provided in Section 516-4. (FPN): For further information, see Spray Application Using Flammable and Combustible Materials, NFPA 33-1989 (ANSI). 516-4.* Fixed Electrostatic Equipment. This section shall apply to any equipment using electrostatically charged elements for the atomization, charging, and (or) precipitation of hazardous materials for coatings on articles or for other similar purposes in which the charging or atomizing device is attached to a mechanical support or manipulator. This includes robotic ARTICLE 516 - SPRAY APPLICATION, DIPPING, COATING 70-527 devices. This section shall not apply to devices that are held or manipulated by hand. Where robotic programming procedures involve manual manipulation of the robot arm while spraying with the high voltage on, the provisions of Section 516-5 shall apply. The installation of electrostatic spraying equipment shall comply with (a) through (j) below. Spray equipment shall be listed or approved. All automatic electrostatic equipment systems shall comply with (a) through (i) below. (a) Power and Control Equipment. Transformers, high-voltage supplies, control apparatus, and all other electric portions of the equipment shall be installed outside of the Class I location as defined in Section 516-2 or be of a type approved for the location. Exception: High-voltage grids, electrodes, electrostatic atomizing heads, and their connections shall be permitted within the Class I location. (b) Electrostatic Equipment. Electrodes and electrostatic atomizing heads shall be adequately supported in permanent locations and shall be effectively insulated from ground. Electrodes and electrostatic atomizing heads that are permanently attached to their bases, supports, reciprocators, or robots shall be deemed to comply with this section. (c) High-Voltage Leads. High-voltage leads shall be properly insulated and protected from mechanical damage or exposure to destructive chemicals. Any exposed element at high voltage shall be effectively and permanently supported on suitable insulators and shall be effectively guarded against accidental contact or grounding. (d) Support of Goods. Goods being coated using this process shall be supported on conveyors or hangers. The conveyors or hangers shall be arranged to (1) assure that the parts being coated are electrically connected to ground with a resistance of 1 megohm or less and (2) prevent parts from swinging. (e) Automatic Controls. Electrostatic apparatus shall be equipped with automatic means that will rapidly deenergize the high-voltage elements under any of the following conditions: (1) stoppage of ventilating fans or failure of ventilating equipment from any cause; (2) stoppage of the conveyor carrying goods through the high-voltage field unless stoppage is required by the spray process; (3) occurrence of excessive current leakage at any point in the high-voltage system; (4) deenergizing the primary voltage input to the power supply. (f) Grounding. All electrically conductive objects in the spray area, except those objects required by the process to be at high voltage, shall be adequately grounded. This requirement shall apply to paint containers, wash cans, guards, hose connectors, brackets, and any other electrically conductive objects or devices in the area. (g) Isolation. Safeguards such as adequate booths, fencing, railings, interlocks, or other means shall be placed about the equipment or incorporated therein so that they, either by their location or character, or both, assure that a safe separation of the process is maintained. (h) Signs. Signs shall be conspicuously posted to (1) designate the process zone as dangerous with regard to fire and accident; (2) identify the 70-528 NATIONAL ELECTRICAL CODE grounding requirements for all electrically conductive objects in the spray area; (3) restrict access to qualified personnel only. (i) Insulators. All insulators shall be kept clean and dry. (j) Other Than Nonincendive Equipment. Spray equipment that cannot be classified as nonincendive shall comply with (1) and (2) below. (1) Conveyors or hangers shall be so arranged to maintain a safe distance of at least twice the sparking distance between goods being painted and electrodes, electrostatic atomizing heads, or charged conductors. Warnings defining this safe distance shall be posted. (2) The equipment shall provide an automatic means of rapidly deenergizing the high-voltage elements in the event the distance between the goods being painted and the eletrodes or electrostatic atomizing heads falls below that specified in item (1) above. 516-5.* Electrostatic Hand-Spraying Equipment. This section shall apply to any equipment using electrostatically charged elements for the atomization, charging, and/or precipitation of materials for coatings on articles, or for other similar purposes in which the atomizing device is hand held or manipulated during the spraying operation. Electrostatic hand-spraying equipment and devices used in connection with paint-spraying operations shall be of approved types and shall comply with (a) through (e) below. (a) General. The high-voltage circuits shall be designed so as not to produce a spark of sufficient intensity to ignite the most readily ignitible of those vapor-air mixtures likely to be encountered, nor result in appreciable shock hazard upon coming in contact with a grounded object under all normal operating conditions. The electrostatically charged exposed elements of the hand gun shall be capable of being energized only by an actuator that also controls the coating material supply. (b) Power Equipment. Transformers, power packs, control apparatus, and all other electric portions of the equipment shall be located outside of the Class I location or be approved for the location. Exception: The hand gun itself and its connections to the power supply shall be permitted within the Class I location. (c) Handle. The handle of the spraying gun shall be electrically connected to ground by a metallic connection and be so constructed that the operator in normal operating position is in intimate electrical contact with the grounded handle to prevent buildup of a static charge on the operator's body. Signs indicating the necessity for grounding other persons entering the spray area shall be conspicuously posted. (d) Electrostatic Equipment. All electrically conductive objects in the spraying area shall be adequately grounded. This requirement shall apply to paint containers, wash cans, and any other electrically conductive objects or devices in the area. The equipment shall carry a prominent, permanently installed warning regarding the necessity for this grounding feature. (e) Support of Objects. Objects being painted shall be maintained in metallic contact with the conveyor or other grounded support. Hooks shall be regularly cleaned to ensure adequate grounding of 1 megohm or less. ARTICLE 516 - SPRAY APPLICATION, DIPPING, COATING 70-529 Areas of contact shall be sharp points or knife edges where possible. Points of support of the object shall be concealed from random spray where feasible; and, where the objects being sprayed are supported from a conveyor, the point of attachment to the conveyor shall be so located as to not collect spray material during normal operation. 516-6.* Powder Coating. This section shall apply to processes in which combustible dry powders are applied. The hazards associated with combustible dusts are present in such a process to a degree, depending upon the chemical composition of the material, particle size, shape, and distribution. (FPN): The hazards associated with combustible dusts are inherent in this process. Generally speaking, the hazard rating of the powders employed is dependent upon the chemical composition of the material, particle size, shape, and distribution. (a) Electric Equipment and Sources of Ignition. Electric equipment and other sources of ignition shall comply with the requirements of Article 502. Portable electric lamps and other utilization equipment shall not be used within a Class II location during operation of the finishing processes. When such lamps or utilization equipment are used during cleaning or repairing operations, they shall be of a type approved for Class II, Division 1 locations, and all exposed metal parts shall be effectively grounded. Exception: Where portable electric lamps are required for operations in spaces not readily illuminated by fixed lighting within the spraying area, they shall be of the type approved for Class II, Division 1 locations where readily ignitible residues may be present. (b) Fixed Electrostatic Spraying Equipment. The provisions of Sections 516-4 and (a) above shall apply to fixed electrostatic spraying equipment. (c) Electrostatic Hand-Spraying Equipment. The provisions of Sections 516-5 and (a) above shall apply to electrostatic hand-spraying equipment. (d) Electrostatic Fluidized Beds. Electrostatic fluidized beds and associated equipment shall be of approved types. The high-voltage circuits shall be so designed that any discharge produced when the charging electrodes of the bed are approached or contacted by a grounded object shall not be of sufficient intensity to ignite any powder-air mixture likely to be encountered nor to result in an appreciable shock hazard. (1) Transformers, power packs, control apparatus, and all other electric portions of the equipment shall be located outside the powder-coating area or shall otherwise comply with the requirements of (a) above. Exception: The charging electrodes and their connections to the power supply shall be permitted within the powder-coating area. (2) All electrically conductive objects within the powder-coating area shall be adequately grounded. The powder-coating equipment shall carry a prominent, permanently installed warning regarding the necessity for grounding these objects. (3) Objects being coated shall be maintained in electrical contact (less than 1 megohm) with the conveyor or other support in order to ensure proper grounding. Hangers shall be regularly cleaned to ensure effective electrical contact. Areas of electrical contact shall be sharp points or knife edges where possible. 70-530 NATIONAL ELECTRICAL CODE (4) The electric equipment and compressed-air supplies shall be interlocked with a ventilation system so that the equipment cannot be operated unless the ventilating fans are in operation. 516-7. Wiring and Equipment Above Class I and II Locations. (a) Wiring. All fixed wiring above the Class I and II locations shall be in metal raceways, rigid nonmetallic conduit, or electrical nonmetallic tubing, or shall be Type MI, TC, SNM, or Type MC cable. Cellular metal floor raceways shall be permitted only for supplying ceiling outlets or extensions to the area below the floor of a Class I or II location, but such raceways shall have no connections leading into or through the Class I or II location above the floor unless suitable seals are provided. (b) Equipment. Equipment that may produce arcs, sparks, or particles of hot metal, such as lamps and lampholders for fixed lighting, cutouts, switches, receptacles, motors, or other equipment having make-and-break or sliding contacts, where installed above a Class I or II location or above a location where freshly finished goods are handled, shall be of the totally enclosed type or be so constructed as to prevent escape of sparks or hot metal particles. 516-8. Grounding. All metal raceways, metal-jacketed cables, and all noncurrent-carrying metal parts of fixed or portable equipment, regardless of voltage, shall be grounded as provided in Article 250.