Zone Exhaust

90.1-2016 BM

This group of building descriptors describes the rate of exhaust and the schedule or control for this exhaust. An exhaust system can serve one thermal block or multiple thermal blocks. Energy is summed at the exhaust system level, not the thermal block level.

 

Kitchen Exhaust Hood Length

Applicability

Exhaust fans in spaces of type Kitchen

Definition

The exhaust hood length

Units

ft 

Input Restrictions

As designed

Baseline building

Same as the proposed design

 

Kitchen Exhaust Hood Style

Applicability

Exhaust fans in spaces of type Kitchen

Definition

The hood style as defined in Table 140.9-A of the Standards

Units

List:  Wall-mounted canopy, Single Island, Double Island, Eyebrow, Backshelf/Passover

Input Restrictions

As designed

Baseline building

Same as the proposed design

 

Kitchen Exhaust Hood Cooking Duty

Applicability

Exhaust fans in spaces of type Kitchen

Definition

The hood cooking duty as defined in Table 6.5.7.1.3 of the 90.1 2010 Standards

Units

List:  Light Duty, Medium Duty, Heavy Duty, Extra Heavy Duty

Input Restrictions

As designed

Baseline building

Same as the proposed design

 

Kitchen: Exhaust Air Flow Rate

Applicability

All Kitchen HVAC zones

Definition

Rate of exhaust from a thermal zone. Standard 90.1 2010 Section 6.5.7.1.3 requires each hood in  kitchen/dining facility with total kitchen hood exhaust airflow rate greater than 5,000 cfm to have an exhaust rate that complies with Table 3.6.5-1. If a single hood, or hood section, is installed over appliances with different duty ratings, then the maximum allowable flow rate for the hood or hood section shall not exceed the Table 3.6.5-1 values for the highest appliance duty rating under the hood or hood section.

Table 3.6.5-1: Maximum Net Exhaust Flow Rate, CFM per Linear Foot of Hood Length

Source: Table 6.5.7.1.3 of Standard 90.1-2016

Type of Hood

Light Duty Equipment

Medium Duty Equipment

Heavy Duty Equipment

Extra Heavy Duty Equipment

Wall-mounted canopy

140

210

280

385

Single island

280

350

420

490

Double island (per side)

175

210

280

385

Eyebrow

175

175

Not allowed

Not allowed

Backshelf/Passover

210

210

280

Not allowed

 

Units

cfm

Input Restrictions

As designed

Baseline building

If the exhaust airflow rate of the proposed design is less than or equal to the exhaust flow rate prescribed in Table 3.6.5-1 above, then the baseline exhaust flow rate will be same as proposed. However, if the kitchen hood exhaust air flow rate for the proposed design is greater than the airflow rate prescribed, then the baseline buildings uses airflow rates equal to that in the table.

 

Kitchen: Demand Ventilation

Applicability

All Kitchen HVAC Zones

Definition

A demand ventilation system uses a light beam and a photo detector to detect the presence of smoke. It also has a temperature sensor to detect heat. The exhaust fan slows down below design levels and both exhaust and replacement airflow rates are reduced when the system detects no smoke or heat.

Units

Unitless

Input Restrictions

As designed

Baseline building

For proposed designs with exhaust air flow rate greater than 5000 CFM, baseline models is required to use demand ventilation system on 75% of the exhaust air and makeup air. Airflow will be reduced by 50% during 50% of kitchen occupied hours.

 

Laboratory Exhaust Rate Type

Applicability

All laboratory zones

Definition

The type of load that dictates lab exhaust rate requirements

Units

List, either: Hood dominated or Load dominated

Input Restrictions

As designed

Baseline building

Same as the proposed design

 

Laboratory: Exhaust Minimum Air Flow Rate

Applicability

All laboratory zones

Definition

Rate of exhaust from a zone

Units

cfm

Input Restrictions

Baseline Building

Baseline Rules

Same As Proposed except for the unoccupied periods, where systems serving laboratory spaces shall reduce the exhaust and makeup air volume during unoccupied periods to the largest of 50% of zone peak air flow, the minimum outdoor air flow rate, or the air flow rate required to comply with applicable codes or accreditation standards.

 

Exhaust Fan Name

Applicability

All HVAC zones

Definition

A reference to an exhaust fan system that serves the thermal block

Units

Text or other unique reference to an exhaust fan system defined in the secondary systems section.

Input Restrictions

As designed

Baseline Rules

Same as the proposed design

 

Exhaust Air Flow Rate

Applicability

All HVAC zones

Definition

Rate of exhaust from a thermal block

Units

cfm

Input Restrictions

As designed

Baseline Rules

Same as the proposed design

 

Exhaust Fan Schedule

Applicability

All HVAC zones

Definition

Schedule indicating the pattern of use for exhaust air from the thermal block. This input should consider the position of fume hood sash opening. For toilets and other exhaust applications, the schedule may coincide with the operation of the exhaust fan system.

Units

Data structure: schedule, fraction

Input Restrictions

As designed

Baseline Rules

Same as the proposed design