SECTION 5.12  SPRAY APPLICATIONS USING FLAMMABLE AND COMBUSTIBLE MATERIALS

Subsection 5.12.1.  Application and Separation

Application

5.12.1.1.  (1)  This Section applies to spray operations involving the use of flammable liquids, combustible liquids or combustible dry powders.

(2)  Despite Sentence (1), this Section does not apply to spray operations that comply with Articles 5.1.3.1. and 5.12.1.2. and the design, operation and maintenance requirements in NFPA 33, “Standard for Spray Application Using Flammable or Combustible Materials”.

Separation for spray operations

5.12.1.2.  If a spray operation is a major occupancy in a building, the spray operation shall be separated from the remainder of the building in accordance with Article 3.1.3.1. of Division B of the Building Code.

Subsection 5.12.2.  Construction

General

5.12.2.1.  (1)  Spray booths and spray rooms shall have walls and ceilings that consist of steel frames covered with sheet steel having a minimum thickness of 1.14 mm or be of equivalent noncombustible construction.

(2)  Walls and ceilings of spray rooms that are susceptible to paint residue accumulations and interior surfaces of spray booths shall be smooth and continuous.

(3)  Floors of spray booths and spray rooms and the operator’s working area shall be of noncombustible materials.

Baffle plates

5.12.2.2.  (1)  Spray booth baffle plates shall be of noncombustible material and be removable or arranged to facilitate cleaning.

(2)  Spray booth baffle plates shall not be located in exhaust ducts.

Overspray collection

5.12.2.3.  (1)  Spray booths and spray rooms shall be provided with overspray collection, such as filters or water wash, to prevent the build-up of combustible deposits on the exhaust fan and ductwork.

(2)  Where filters are used as for overspray collection, supports and holders for the filters shall be constructed of noncombustible materials.

(3)  Overspray collection filters shall be readily removable or accessible for cleaning or replacement.

(4)  Filters shall not be alternately used for different types of coating materials if the combination of materials might result in spontaneous heating or ignition.

(5)  Maintenance procedures shall be established to ensure that overspray collection filters are replaced before excessive restriction to airflow occurs.

(6)  Overspray collectors shall be inspected after each period of use and clogged filters shall be discarded and replaced.

(7)  A water-wash filtration system shall be used when applying materials known to be highly susceptible to spontaneous heating or spontaneous ignition.

Fan blades and casings

5.12.2.4.  Fan blades and casings in exhaust blowers for spray booths and spray rooms shall be non‑ferrous, or the fan shall be constructed so that a movement of the wheel or shaft will not cause two ferrous parts of the fan to rub or strike together.

Subsection 5.12.3.  Ventilation

Ventilation

5.12.3.1.  (1)  Ventilation shall be provided in all spraying areas to maintain

(a)   the concentration of flammable vapours at or below 25% of their lower explosive limit, and
(b)   the concentration of combustible dusts at or below 50% of their minimum explosible concentration or 15g/m³ when the minimum explosible concentration cannot be established.

Exhaust for spray booths

5.12.3.2.  Subject to Article 5.12.3.3., the exhaust air velocity at any opening in a spray booth shall be at least 30 m/min.

Exhaust for electrostatic spraying

5.12.3.3.  Electrostatic spraying shall have an exhaust air velocity of at least 18 m/min at any opening in a spray booth.

Combined ducting

5.12.3.4.  A separate exhaust duct shall be provided for each spray booth, except that a common duct may be used if it serves spray booths having a combined open frontal area of not more than 1.8 m².

Exhaust air

5.12.3.5.  Air exhausted from spray operations shall not be recirculated, except where recirculation is acceptable, as described in NFPA 33, “Standard for Spray Application Using Flammable or Combustible Materials”.

Monitoring air velocity

5.12.3.6.  (1)  Gauges or alarms that indicate when the air velocity is less than the air velocity required by Article 5.12.3.2. or 5.12.3.3. shall be installed for spray booths.

(2)  When the gauge or alarm indicates that the air velocity is less than that required by Article 5.12.3.2. or 5.12.3.3., immediate corrective action shall be taken to remedy the condition that has resulted in the reduction of the ventilation.

Subsection 5.12.4.  Exhaust Ducts

Duct support and construction

5.12.4.1.  Exhaust ducts for spray booths and spray rooms shall be securely supported and constructed of sheet steel in accordance with Table 5.12.4.A.

TABLE 5.12.4.A.

Forming Part of Article 5.12.4.1.

Clearances

5.12.4.2.  Subject to Article 5.12.4.3., a clearance of 457 mm shall be maintained between unprotected combustible materials and ducts venting spray booths and spray rooms.

Collars

5.12.4.3.  (1)  Where exhaust ducts pass through combustible roofs or partitions, metal collars shall provide not less than a 100 mm clearance between the duct and combustible material.

(2)  The space between the duct and combustible material shall be sealed with noncombustible insulating material.

Access doors

5.12.4.4.  Exhaust ducts for spray booths and spray rooms shall be provided with access doors for cleaning purposes.

Exhaust outlet locations

5.12.4.5.  (1)  Except for water-wash filtration systems, the exhaust outlet to atmosphere from spray booths and spray rooms shall

(a)   be 1.8 m from any combustible exterior wall or roof, and

(b)   be located so that the air does not discharge toward any combustible surface or unprotected opening within 7.5 m.

Subsection 5.12.5.  Electrical Equipment

Electrical equipment

5.12.5.1.  Electrical equipment within the spraying area, including lighting fixtures, shall conform to Part 1, Sections 18 and 20 of the Electrical Safety Code made under the Electricity Act, 1998.

Motors for exhaust fans

5.12.5.2.  Electric motors for exhaust fans shall not be placed inside spray booths, spray rooms or ducts.

Grounding

5.12.5.3.  Metal parts of spray booths, exhaust ducts and piping systems conveying flammable liquids or combustible liquids shall be electrically grounded.

Subsection 5.12.6.  Flammable Liquids and Combustible Liquids

Storage and handling

5.12.6.1.  Flammable liquids and combustible liquids for use in spraying areas shall be stored and handled in conformance with Part 4, and at no time shall the amount of flammable liquids and combustible liquids in the spraying areas exceed one day’s supply.

Paint storage

5.12.6.2.  Flammable liquids and combustible liquids shall be kept in closed containers when not in use.

Thinners and solvents

5.12.6.3.  Thinners and solvents shall be dispensed only from listed and labelled safety cans.

Pump discharge relief valves

5.12.6.4.  Where flammable liquids are supplied to spray nozzles by positive displacement pumps, the pump discharge line shall be provided with a suitable relief valve discharging to the pump suction or to a safe remote location.

Subsection 5.12.7.  Control of Fire Hazards

Interlocks

5.12.7.1.  (1)  The spraying equipment for spray booths and spray rooms shall be interlocked to shut down in the event of

(a)   a failure of the ventilation system,
(b)   a failure of the circulating water pump of a water-wash filtration system, or
(c)   a failure of the filter roll-down mechanism of an overspray collection system.

Cleaning and residue disposal

5.12.7.2.  (1)  The inner surfaces of spray booths and spray rooms shall be cleaned of combustible residue as often as necessary to prevent a fire hazard.

(2)  Combustible residue from cleaning operations shall, on the same day as the cleaning operations, be removed from the premises or placed in receptacles conforming to Sentence 2.4.1.3.(3).

(3)  Strippable coatings or removable combustible coverings, such as thin paper and static dissipative plastic sheets, may be used on walls and floors in spray booths and spray rooms to facilitate cleaning operations.

Filter pads and rolls

5.12.7.3.  Discarded filter pads and filter rolls shall be removed to a safe location or placed in a water-filled metal container and disposed of after each day’s operation.

5.12.7.4.  RESERVED

Heating equipment

5.12.7.5.  Space-heating appliances, steam pipes and other hot surfaces shall not be located in an area subject to accumulation of deposits of combustible residue from spray operations.

Ignition sources

5.12.7.6.  Open flame or spark producing devices shall not be used within a spraying area, unless separated from the area by a vapour-tight fire separation having a fire-resistance rating not less than 1 h.

Subsection 5.12.8.  Fire Protection Equipment

Portable extinguishers

5.12.8.1.  Portable extinguishers shall be installed near spraying areas in conformance with Section 6.2.

Sprinkler installations

5.12.8.2.  (1)  Except as permitted in Sentences (2) and (3), automatic sprinkler protection shall be provided in each spraying area, spray booth and spray room in conformance with NFPA 13, “Standard for the Installation of Sprinkler Systems”.

(2)  Where spraying operations are confined within a spray booth, fire protection may be provided for the spray booth only, in conformance with NFPA 33, “Standard for Spray Application Using Flammable or Combustible Materials”.

(3)  This Article does not apply where the existing situation is approved and does not endanger life safety, or approved alternative measures to the requirements set out in this Article are taken to provide life safety.

Sprinkler head protection

5.12.8.3.  (1)  Sprinkler heads in spray booths and spray rooms shall be protected with lightweight paper bags or cellophane bags having a thickness of not more than 0.08 mm.

(2)  Bags protecting sprinkler heads shall be replaced before they have accumulated deposits that impair the timely operation of the sprinkler head.

Subsection 5.12.9.  Drying Operations

Spray booths used for drying

5.12.9.1.  Except as permitted in Article 5.12.9.4., spray booths, spray rooms or other enclosures used for spraying operations shall not be used for drying by any arrangement that could cause an increase in the surface temperatures of the spray booths, spray rooms or other enclosures.

Location of equipment

5.12.9.2.  Except as provided in Articles 5.12.9.3. and 5.12.9.4., drying or curing equipment that utilizes components capable of producing ignition, such as an open flame, a spark, or a hot surface, shall not be installed in or near a spraying area.

Location near spraying area

5.12.9.3.  (1)  Equipment described in Article 5.12.9.2. may be installed in an area adjacent to the spraying area provided the adjacent area is equipped with a ventilating system arranged to

(a)   purge the drying space before the heating system can be started,
(b)   maintain the atmosphere at any source of ignition at or below 25% of the lower explosive limit of any combustible or flammable materials in use, and
(c)   automatically shut down the heating system in the event of failure of the ventilating system.

Spray booths used for drying

5.12.9.4.  (1)  Spray booths may be used for drying operations where

(a)   the spray booth conforms to the appropriate requirements for drying ovens in Section 5.18,
(b)   the interior of the enclosure is kept reasonably free of overspray deposits,
(c)   portable drying apparatus, if used, is of the infrared type, and such apparatus, wiring and connections are removed from the enclosure during spraying operations, and
(d)   interlocks are installed to

(i)   prevent the use of spraying apparatus while the drying operation is taking place,
(ii)   provide for the purging of the enclosure of spray vapours for a minimum of 3 min before the drying apparatus can be energized,
(iii)   ensure that the ventilating system maintains the concentration of flammable vapours at or below 25% of the lower explosive limit within the enclosure during the drying process, and
(iv)   ensure that the drying apparatus will automatically shut off in the event of failure of the ventilating system.

Subsection 5.12.10.  Electrostatic Spraying

Application

5.12.10.1.  This Subsection applies to electrostatic spray-coating processes involving the use of flammable liquids or combustible liquids.

Equipment location

5.12.10.2.  (1)  Electrical components, including transformers, power packs and control equipment for electrostatic spray applications, shall be located in an area where the vapour concentration of flammable liquids or combustible liquids cannot exceed 25% of the lower explosive limit.

(2)  Sentence (1) does not apply to high voltage grids and their connections.

Interlocks

5.12.10.3  (1)  Electrostatic spraying equipment shall be provided with automatic controls that will operate without a time delay to disconnect power to high voltage transformers and to signal the operator of the equipment if

(a)   the air supply system, the ventilating fan or the conveyor system stops,
(b)   a ground occurs at any point on the high voltage system, or
(c)   any clearances are reduced below those required by Article 5.12.10.5.

Insulators

5.12.10.4.  Insulators shall be kept clean and dry.

Clearances

5.12.10.5.  A clearance space that is equivalent to twice the sparking distance shall be maintained between the articles being painted and any electrodes or conductors.

Drip plates and screens

5.12.10.6.  Drip plates and screens subject to paint deposits shall be removable for cleaning.

Insulating and grounding

5.12.10.7.  High voltage components, including atomizing heads, shall be insulated and protected against mechanical damage and accidental contact or grounding.

Automatic grounding

5.12.10.8.  An automatic means shall be provided for grounding the electrode system when it is de-energized.

Operating distances

5.12.10.9.  Items being electrostatically sprayed shall be neither held by hand nor suspended in such a manner as to reduce the proper operating distance from the atomizing heads.

Distance to processing areas

5.12.10.10.  Electrostatic spraying equipment shall be located 1.5 m from processing equipment and isolated from other areas by grounded guards and fences of conducting material.

Surface temperatures

5.12.10.11.  The surface temperature of equipment in a spraying area shall not exceed 66°C.

Precautions against shock

5.12.10.12.  High voltage circuits shall be designed so that any discharge will not ignite vapour-air mixtures or create a shock hazard.

Spray gun energy supply

5.12.10.13.  The energy supply to hand-held spray guns shall be controlled by a switch that also controls the coating material supply.

Spray gun operation

5.12.10.14.  Spray gun handles shall be grounded and have a metallic connection that is in direct contact with the operator’s hand during spraying.

Grounding

5.12.10.15.  All electrically conductive objects in a spraying area shall be grounded.

Paint accumulations

5.12.10.16.  Hooks and other supports for sprayed items shall be kept clean and free of paint.

Warning signs

5.12.10.17.  (1)  Signs shall be conspicuously posted near a spraying area that

(a)   indicate the minimum clearance space required by Article 5.12.10.5.,
(b)   indicate the need for grounding of all electrically conductive objects in the spraying area, and
(c)   contain the phrase “DANGER – Electrostatic Spray Coating Area”, or otherwise identify the spraying area as dangerous.

Fixed extinguishing equipment

5.12.10.18.  Spraying areas shall be located in rooms protected by listed and labelled automatic fixed extinguishing equipment.

Subsection 5.12.11.  Dry Powder-Coating Using Spray Guns

Application and location

5.12.11.1.  (1)  This Subsection applies to coating operations involving the use of combustible dry powders applied by powder spray guns or electrostatic powder spray guns.

(2)  Coating operations referred to in Sentence (1) shall be performed in

(a)   ventilated and enclosed powder-coating rooms of noncombustible construction, or
(b)   spray booths.

Location of electrical equipment

5.12.11.2.  With the exception of charging electrodes and their connections, transformers, power packs, control apparatus and all other electrical components shall be located outside the powder-coating area.

Working temperatures

5.12.11.3.  If a part to be coated is preheated prior to the application of the powder, the temperature of the part shall not exceed the ignition temperature of the powder being used.

Grounding

5.12.11.4.  (1)  Powder transport, application and recovery equipment shall be grounded.

(2)  A sign shall be conspicuously posted indicating the necessity of grounding the equipment and objects identified in Sentence (1).

Separators

5.12.11.5.  Separators shall be used to prevent tramp iron or other spark-producing materials from being introduced into the powders being applied.

Recovery systems

5.12.11.6.  Waste air-suspended powders shall be removed by exhaust ducts to a powder recovery system and shall not be released to the outside atmosphere.

Vacuum cleaning

5.12.11.7.  Accumulations of waste dust from dry powder finishes shall be removed by vacuum cleaning equipment.

Contact points

5.12.11.8.  Objects being coated shall be maintained in contact with the conveyor or other support.

Hangers

5.12.11.9.  Hangers for objects being coated shall be kept clean and have sharp points or edges at areas of contact.

Smoking prohibited

5.12.11.10.  (1)  Smoking shall not take place in powder-coating areas and in powder storage rooms.

(2)  Signs prohibiting smoking that meet the requirements of Article 2.4.3.2. shall be conspicuously posted in all powder-coating areas and powder storage rooms.