N.Y.C. Admin. Code § MC 511: Section MC 511: Dust, Stock and Refuse Conveying Systems

511.1 Dust, stock and refuse conveying systems.

Dust, stock and refuse conveying systems shall comply with the provisions of Section 510 and Sections 511.1.1 through 511.2.

511.1.1 Collectors and separators.

Collectors and separators involving such systems as centrifugal separators, bag filter systems and similar devices, and associated supports shall be constructed of noncombustible materials and shall be located on the exterior of the building or structure. A collector or separator shall not be located nearer than 10 feet (3048 mm) to combustible construction or to an unprotected wall or floor opening, unless the collector is provided with a metal vent pipe that extends above the highest part of any roof within a distance of 30 feet (9144 mm).

Exceptions:

1. Where dust producing equipment requires an aggregate dust collection flowrate less than 1,500 ft

3

per min (708 liters per second), collectors such as "Point of Use" collectors, close extraction weld fume collectors, spray finishing booths, stationary grinding tables, sanding booths, and integrated or machine-mounted collectors shall be permitted to be installed indoors provided the installation is in accordance with the New York City Fire Code and the New York City Electrical Code.

2. Collectors in independent exhaust systems handling combustible dusts shall be permitted to be installed indoors provided that such collectors are installed in compliance with the New York City Fire Code and the New York City Electrical Code.

511.1.2 Discharge pipe.

Discharge piping shall conform to the requirements for ducts, including clearances required for high-heat appliances, as contained in this code. A delivery pipe from a centrifugal separator collector shall not convey refuse directly into the firebox of a boiler, furnace, dutch oven, refuse burner, incinerator or other appliance.

511.1.3 Conveying systems exhaust discharge.

An exhaust system shall discharge to the outside of the building either directly by flue or indirectly through the bin or vault into which the system discharges except where the contaminants have been removed. Exhaust system discharge shall be permitted to be recirculated provided that the solid particulate has been removed at a minimum efficiency of 99.9 percent at 10 microns (10.01 mm), vapor concentrations are less than 25 percent of the LFL, and approved equipment is used to monitor the vapor concentration.

511.1.4 Spark protection.

The outlet of an open-air exhaust terminal shall be protected with an approved metal or other noncombustible screen to prevent the entry of sparks.

511.1.5 Explosion relief vents.

A safety or explosion relief vent shall be provided on all systems that convey combustible refuse or stock of an explosive nature, in accordance with the requirements of the New York City Building Code.

511.1.5.1 Screens.

Where a screen is installed in a safety relief vent, the screen shall be attached so as to permit ready release under the explosion pressure.

511.1.5.2 Hoods.

The relief vent shall be provided with an approved noncombustible cowl or hood, or with a counterbalanced relief valve or cover arranged to prevent the escape of hazardous materials, gases or liquids.

511.2 Exhaust outlets.

Outlets for exhaust that exceed 600°F (315°C) shall be designed as a chimney in accordance with Table 511.2.

Table 511.2 Construction Clearance and Termination Requirements for Single-Wall Metal Dust, Stock and Refuse Conveying Systems

Serving Temperature Range 

Minimum Thickness

Termination

Clearance

Walls (inch)

Lining

Above roof opening (feet)

Above any part of building within (feet)

Combustible construction (inches)

Noncombustible construction

10

25

50

Interior inst.

Exterior inst.

Interior inst.

Exterior inst.

High-heat appliances (Over 2,000°F)

a

0.127 (No. 10 MSG)

4 1/2" laid on 4 1/2" bed

20

—

—

20

See Note c

Low-heat appliances (1,000°F normal operation)

0.127 (No. 10 MSG)

None

3

2

—

—

18

6

Up to 18" diameter, 2" Over 18" diameter, 4"

Medium-heat appliances (2,000°F maximum)

b

0.127 (No. 10 MSG)

Up to 18" dia. – 2 1/2" Over 18" – 4 1/2" On 4 1/2" bed

10

—

10

—

36

24

Up to 18" diameter, 2" Over 18" diameter, 4"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, °C = ((°F) - 32)/1.8.

a. Lining shall extend from bottom to top of outlet.

b. Lining shall extend from 24 inches below connector to 24 feet above.

c. Clearance shall be as specified by the design engineer and shall have sufficient clearance from buildings and structures to avoid overheating combustible materials (maximum 160°F).