Part 5

Division B

Part 5

 

5.6.2.3.

Q1:

 

Does aggregate capacity refer to material in the liquid or gaseous state?

R1:

 

It refers to the total volume of material in the gaseous state at 60°F and 1 atmosphere pressure.

 

 

Q2:

 

How is the aggregate capacity or volume determined for a material stored in the liquid state?

R2:

 

Please refer to the 2015 Fire Code Compendium, Appendix E

 

 

Q3:

 

Does Article 5.6.2.3. of Division B apply to compressed air and oxygen?

R3:

 

This article applies to compressed air and oxygen if the quantities exceed 150 kg (see Article 5.6.1.1. of Division B). Compressed air and oxygen are non-flammable gases that are non corrosive and non poisonous.

 

 

Q4:

 

What is meant by the word "opening"?

R4:

 

The word "opening" refers to any aperture in the building exterior wall through which gases could enter.

 

 

Q5:

 

Does an opening include a window that is fixed shut?

R5:

 

No, as gases cannot enter the building through this sealed closure.

 

5.6.2.4.(2)

Q1:

 

What is meant by referring to a gas as being lighter than or heavier than air?

R1:

 

This refers to the density of the gas when compared to the density of air. A gas that has a density that is less than the density of air is lighter than air. Conversely, a gas that has a density that is more than the density of air is heavier than air.

 

5.6.2.7.

Q1:

 

If a compressed gas that is lighter than air reacts with a compressed gas that is heavier than air, what is the spatial separation or barrier size that will be required to separate the cylinders?

R1:

 

This article applies to any gases that react with one another, regardless of their specific gravity.

 

5.10.1.1.

Q1:

 

Does Section 5.10 of Division B apply to courtesy lumber cutting operations in a retail setting, such as a home improvement store?

R1:

 

Section 5.10 applies to buildings or equipment where combustible dusts are produced in quantities that create an explosion or fire hazard. A courtesy lumber cutting operation in a retail setting would not likely produce the quantities or the concentrations of combustible dust needed to create an explosion or fire hazard, based on the limited and intermittent cutting that typically occurs in these circumstances. However, each case should be evaluated individually to determine if Section 5.10 applies. It should be noted that poor housekeeping practices that lead to the accumulation of combustible waste (including saw dust) are regulated by Section 2.4 of Division B.

 

5.10.1.5.(3)(a)

Q1:

 

What is meant by the phrase "return air will not create an explosion hazard inside the building"?

R1:

 

The intent of Clause 5.10.1.5.(3)(a) of Division B is to ensure that hazardous quantities of combustible dust are not returned to the building from the dust collector’s exhaust. Poorly filtered return-air could, under extreme conditions, carry high concentrations of dust that could deflagrate if an ignition source is encountered inside the building. More likely though is that the return air will carry low concentrations of dust that could lead to a dust build-up on exposed surfaces over time. This could create an explosion hazard if it is shaken or blown down, creating an ignitable explosive dust cloud. However, good housekeeping practices that keep these surfaces clean of dust accumulations will mitigate this hazard.

 

5.10.1.12.

Q1:

 

Does Article 5.10.1.12. of Division B apply to any equipment that creates combustible dust through cutting, sawing, planing or lathing operations?

R1:

 

No. Article 5.10.1.12. is not intended to apply to equipment conducting operations such as cutting, sawing, planing or lathing. It is intended to apply to shellers, crackers, crushers, grinding machines and pulverizers, and other similar equipment designed to reduce coarse material into finer particulate matter through the use of violent grinding or crushing action often leading to the generation of combustible dust. Any metal that is drawn into this type of equipment could create significant sparks or even cause small pieces of hot metal to break off inside the equipment and then be drawn into the dust exhaust duct to the dust collector.

 

5.12.2.1.

Q1:

 

What area is deemed the "operator’s working area"?

R1:

 

The operator’s working area is the area that the operator is likely to occupy while spray painting.

 

 

Q2:

 

Would a layer of drywall attached to both sides of a steel framework be acceptable for the wall and ceiling construction of a spray booth as being of "equivalent" to sheet steel?

R2:

 

A drywall interior finish is not considered to be equivalent noncombustible constuction.

 

5.12.3.1.

Q1:

 

What level of ventilation is required in a spraying operation to maintain the concentration of flammable vapours at 25 percent of the lower explosive limit (LEL)?

R1:

 

Tables A.9.2.6.2.2. (a) and (b) of NFPA 86, "Standard for Ovens and Furnaces", provide information on the ventilation rate required for a number of different solvents. The ventilation required can also be calculated using the following formula: V = 4 x (0.83 x Sp.G./V.D.) x ([100 - LEL]/LEL) xL where, V is the required ventilation rate expressed in m3/min., Sp.G. is the specific gravity of the flammable liquid, V.D. is the vapour density of the flammable liquid, LEL is the lower explosive limit of the flammable liquid, and, L is the application rate of the flammable liquid expressed in litres/min. L can be calculated by multiplying the amount of paint or coating being applied per minute by the percentage of flammable liquid in the paint or coating.

 

5.12.5.1.

Q1:

 

What is the ‘spraying area’ for a spray operation not located in a spray booth?

R1:

 

Spraying area is defined in Article 1.4.1.2. of Division A as ‘the area that is within 6 m of a spray booth or spraying operation and that is not separated therefrom by a vapour-tight separation’. As such, the spraying area for an open-air spraying operation is a zone that vertically and horizontally surrounds the operation. The boundaries of the zone terminate 6 metres from the spraying operation in all directions, or at vapour-tight separations if they are located closer than 6 metres to the operation.

 

 

Q2:

 

What is the spraying area for a spray operation confined to a spray booth?

R2:

 

If the spray booth is enclosed by vapour-tight construction the spray booth is the spraying area. If the spray booth has construction that is not vapour-tight the spraying area consists of the spray booth and the space that is located within 6 m of all openings in the spray booth or to vapour tight separations that are located closer than 6 m.

 

5.12.8.2.

Q1:

 

Can a carbon dioxide or dry chemical extinguishing system be used instead of sprinklers in an enclosed automobile paint spray booth?

R1:

 

Yes, provided that the automobile spray booth satisfies the definition of the term spray booth in Division A and the fire protection system in the booth complies with NFPA 33, "Standard for Spray Application Using Flammable or Combustible Materials". This standard permits the use of a number of extinguishing agents including carbon dioxide and dry chemical.

 

5.13.3.4.

Q1:

 

What is an overflow pipe?

R1:

 

An overflow pipe is used in a dip tank to drain flammable or combustible liquids from the tank to a safe location in the event of an overfill of the tank. This prevents liquid spillage and the possible spread of fire from the tank to other areas of the room.