Smoke Exhaust systems - Emergency?

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mshields

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Location
Boston, MA
I have always fed smoke exhaust fans with MI cable. In Boston, the FD explicitly requires it, Article 700 has an informational note indicating that it may be considered part of the Emergency system and in general, I wouldn't want to have to explain why I didn't consider it worthy of such treatment.

BUT, does the IBC (we go by 2009 here in Boston and will in a years time be going by 2015) explicitly require 2 hour feeders? And/or explicitly label smoke exhaust fans as being Emergency, a label that would trigger the requirements of Article 700?
 

ron

Senior Member
Is it smoke exhaust or more formally smoke control? It is important to determine formally what the HVAC guys are calling it (and designing it to what code). If it is smoke control, then it is Article 701

2702.2.2 Smoke control systems. Standby power shall be provided for smoke control systems in accordance with Section 909.11.

909.11 Power systems. The smoke control system shall be supplied with two sources of power. Primary power shall be from the normal building power systems. Secondary power shall be from an approved standby source complying with Chapter 27 of this code. The standby power source and its transfer switches shall be in a room separate from the normal power transformers and switch gears and ventilated directly to and from the exterior. The room shall be enclosed with not less than 1-hour fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 712, or both. The transfer to full standby power shall be automatic and within 60 seconds of failure of the primary power system.
 

nhfire77

Senior Member
Location
NH
I have always fed smoke exhaust fans with MI cable. In Boston, the FD explicitly requires it, Article 700 has an informational note indicating that it may be considered part of the Emergency system and in general, I wouldn't want to have to explain why I didn't consider it worthy of such treatment.

BUT, does the IBC (we go by 2009 here in Boston and will in a years time be going by 2015) explicitly require 2 hour feeders? And/or explicitly label smoke exhaust fans as being Emergency, a label that would trigger the requirements of Article 700?

More than likely its classified as smoke control in Boston and the feeders would require a 2hr rating.
 

mshields

Senior Member
Location
Boston, MA
Smoke Control vs Smoke Exhaust?

Smoke Control vs Smoke Exhaust?

I would think that smoke exhaust is covered by the term smoke control? albeit with smoke control not necessarily being smoke exhaust. e.g. smoke control could be a floor pressurization scheme.

But that's just my intuition. Please tell me - what is the distinction AND if the HVAC guys are calling it smoke exhaust, how does that change what is required?

Thanks,

Mike
 

ron

Senior Member
Please tell me - what is the distinction AND if the HVAC guys are calling it smoke exhaust, how does that change what is required?

If it doesn't fall within the criteria of "smoke control" design as written in the building and mechanical code, then the building code in Chapter 27 (Electrical), doesn't require you to do anything special with it electrically.

From the IBC referenced from Chapter 27.
SECTION 909 SMOKE CONTROL SYSTEMS
909.1 Scope and purpose. This section applies to mechanical or passive smoke control systems when they are required by other provisions of this code. The purpose of this section is to establish minimum requirements for the design, installation and acceptance testing of smoke control systems that are intended to provide a tenable environment for the evacuation or relocation of occupants. These provisions are not intended for the preservation of contents, the timely restoration of operations or for assistance in fire suppression or overhaul activities. Smoke control systems regulated by this section serve a different purpose than the smoke- and heat-venting provisions found in Section 910. Mechanical smoke control systems shall not be considered exhaust systems under Chapter 5 of the International Mechanical Code.
 
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