Intake-Exhaust separation on packaged unit 1

[Gene M.]

A client has made a comment on a design to provide additional ductwork on a packaged rooftop unit to ensure the intake and exhaust are 10 feet apart. Currently the packaged unit has factory installed hoods which are on adjacent corners.

I'm aware of the 10-foot requirement between environmental air exhausts and mechanical air intakes under NYC Mechanical Code 501.3.1 (3) but it seems pretty implausible that literally every packaged rooftop unit in NYC was specified and installed in violation of code, and I want to say I was given a reason/exception for this situation but I can not find it. Is there a code citation or similar that justifies having intake and exhaust hoods on the same unit within the 10-foot (and 3-foot vertical) separation?

 

[nuuvox000]

From the IMC commentary:

Item 3 details the provisions for termination points for exhaust ducts that convey environmental air. "Environmental Air" is defined in section 202 as "air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust, domestic clothes dryer exhaust, and parking garage exhaust."

It seems the air you're exhausting from a packaged unit does not meet the definition of "environmental air" so the section does not apply.

 

[BronYrAur]

Chicago code used to read that way, but now there is an exception for packaged units. Many packaged units out there have ductwork extending the intakes 10' away. No longer required in Chicago. Double-check your local code.

 

[V Infra]

we have requirement of Pressurization system in MCC room details are given as below

ROOM AIR CONDITION SIZING CAPACITY SIZING CALCULATION
ROOM DETAILS
LENGTH 47.57 (FOOT) TOTAL AREA SQ. FOOT 1284.39 SQ.FT
WIDTH 27 (FOOT)
HEIGHT 12.5 (FOOT) 4.5 4500

DOORS PRESENT IN ROOM QTY LENGTH(FOOT) WIDTH(FOOT)
2 6.6 6.6

NOS OF PERSONS WHO MAY UTILIZE THE ROOM 10 NOS 440

ELECTRICAL APPLIANCES IN ROOM
ELECTRICAL EQUIPMENTS ELECTRICAL LIGHTING
QTY WATT DESCRIPTION TOTAL QTY. WATT TOTAL
5 298 OUTLETS 1490 24 40 960
1 12500 PIMCC 12500 0
1 8500 L.XMER 8500 0
1 2500 MLDB 2500 0
1 7500 OTHERS 7500 0
CONSIDERING 25% EXTRA LOSS 8122.5 CONSIDERING 40% EXTRA LOSS 384
TOTAL 40612.5 TOTAL 1344
CALCULATION
ROOM BTU 40137.1875
OCCUPANT BTU 4400
EQUIPMENT BTU 142143.75 REQUIRED A.C. (TON) 16.82441146
LIGHTING BTU 5712
DOORS BTU 5000
HEIGHT BTU(ABOVE 8FT ADD 1000BTU FOR EACH FT. 4500 REQUIRED A.C. (kW) 59.16897925
TOTAL HEAT LOAD (BTU) 201892.9375
TOTAL COOLING REQUIRED (BTU) 201892.9375