Energy Code Ace - NA7.16.3 Construction Inspection for Simple Turndown Control

NA7.16 Lab Exhaust Ventilation System Acceptance Test

NA7.16.1 - Construction Inspection for VAV Lab Exhaust System with Occupancy Control

Verify and document the following prior to functional testin

(a) Test and balance report confirms correspondence between design values on plans and specification and measure values to within 10%:

Area and volume of each lab space.
Design airflow rate of lab space, (cfm).
Occupied minimum airflow rate of each lab space, (cfm).
Unoccupied minimum airflow rate of each lab spaced, (cfm).
Design inlet airflow rate o exhaust fan system, (cfm).
Power of exhaust fan system at design conditions, (watts).
Calculate wats/cfm at design conditions. Item (a)6 divided by item (a)5.

(b) Listing of fume hoods design airflow rate by VAV (variable air volume) vs CV (constant volume) by space. When the total design airflow rate of fume hoods is greater than the unoccupied minimum airflow rate of the space, all fume hoods in the space shall be VAV.

(c) Pressure independent flow control valves are used.

(d) Document whether system has air filtration, scrubbers, or other air treatment devices.

(e) Document fan power requirements described in (e)1 through (e)3 based on type of fan control used: none, simple turndown, wind responsive, contaminant monitoring.

If control is “none,” and system has one of the filtration methods in item (d), water/cfm in item (a)7 shall be no greater than 0.85 watts/cfm of exhaust fan system airflow. Alternatively, the rated fan power does not surpass fan kW_budget as calculated per Section 140.4(c)1A.
If control is “none,” and system does not have one of the filtration methods in item (d), watts/cfm in item (a)7 shall be no greater than 0.65 watts/cfm of exhaust fan system. Alternatively, the fan power does not surpass fan kW_budget as calculated per Section 140.4(c)1A.
If control is “simple turndown,” “wind responsive,” or “contaminant monitoring,” exhaust fan system watts per cfm in item (a)7 shall be no greater than 1.3 watts per cfm of exhaust fan system airflow, and fan system shall comply with the applicable acceptance testing requirements in Nonresidential Reference Appendices NA7.16.3 through NA7.16.8.

NA7.16.2 Functional Testing for VAV Lab Exhaust System with Occupancy Control

If control signals have been calibrated to measure flow rates and power consumption, recorded control signals are acceptable methods of measurement.

Step 1: Simulate design conditions by opening all fume hood sashes and other exhaust devices such as snorkels to their design open position and occupy all lab spaces served by the exhaust fan system.

(a) Verify that the occupant sensors can detect occupants in all portions of the spaces and are reporting occupied occupancy status to controller.

(b) Verify that the inlet airflow rate of the exhaust fans meets the design flowrate.

(c) Verify fan power under design conditions.

(d) Measured power under design conditions shall be no greater than the design fan power.

Step 2: Simulate minimum flowrate under occupied conditions by adjusting fume hoods and other exhaust devices. Adjust the thermostatic control so that the space temperature is within the dead band.

(a) Verify that the occupant sensors can detect occupants in all portions of the spaces and are reporting occupied occupancy status to controller.

(b) Verify that the total exhaust airflow rate of each space meets the minimum allowed occupied airflow rate.

(c) Verify fan power under design conditions.

(d) Measured power under minimum flowrate occupied conditions [Step 2(c)] shall be no greater than measured power under design conditions [Step 1(c)].

Step 3: Simulate minimum flowrate under unoccupied conditions by adjusting fume hoods and other exhaust devices and vacate all lab spaces served by the exhaust fan system for at least 20 minutes so occupant control treats lab spaces as unoccupied. Adjust the thermostatic control so that the space temperature is within the dead band.

(a) Verify that the occupant sensors are reporting unoccupied occupancy status to controller.

(b) Verify that the total exhaust airflow rate of each space meets the minimum allowed unoccupied flowrate.

(c) Verify fan power under minimum flowrate occupied conditions.

(d) Measured power under minimum flowrate unoccupied conditions [Step 3(c)] shall be no greater than measured power under minimum flowrate occupied conditions [Step 2(c)].

NA7.16.3 Construction Inspection for Simple Turndown Control

Requirements for simple turndown control are required in addition to requirements for VAV lab exhaust system with occupancy controls in NA7.16.1 and NA7.16.2 if the builder uses simple turndown controls to meet fan system power consumption requirements.

(a) Confirm that design values on plans and specifications and measured values are within 10%:

1. Design inlet airflow rate of exhaust fan system (cfm).

2. Power of exhaust fan system at design conditions (watts).

3. Inlet airflow rate of exhaust fan system at occupied minimum acceptable airflow rate (cfm).

4. Power of exhaust fan system at occupied minimum acceptable airflow rate (watts).

5. Power of exhaust fan system at 60% of design exhaust fan system airflow rate (watts).

6. Calculate watts/cfm at maximum design conditions, Item (a)2 divided by item

(b) Measured occupied minimum acceptable exhaust fan system inlet airflow rate [item (a)3] is no greater than 60% of measured design exhaust fan system airflow rate [item(a)1].

(c) Measured exhaust fan system power at 60% of design fan system airflow rate [item (a)5] is no greater than 40% of measured exhaust fan system power at design exhaust fan system airflow rate [item (a)2].

NA7.16.4 Functional Testing for Simple Turndown Control

If control signals have been calibrated to measured flow rates and power consumption, recorded control signals are acceptable methods of measurement.

Step 1: Simulate design conditions. Adjust the thermostatic control so that the space temperature is within the dead band.

Verify that the occupant sensors can detect occupants in all portions of the spaces and are reporting occupied occupancy status to controller.
Verify that the exhaust fan system inlet airflow rate (cfm) meets the design airflow rate.
Record fan system power (watts).

Step 2: Simulate turndown airflow rate. Adjust the thermostatic control so that the space temperature is within the dead band.

Record exhaust fan system inlet airflow rate (cfm).
Confirm that the airflow rate entering fan system for turndown airflow rate [Step 2(b)] is no greater than 60% of the exhaust fan system design airflow rate [Step 1(b)].

Step 3: Simulate 60% of design airflow rate. Adjust thermostatic control so that the space temperature is within the dead band.

Record fan system power (watts).
Confirm that the fan system power under 60% design airflow rate [Step 3(a)] is no greater than 40% of the exhaust fan system design airflow rate [Step 1(c)].

NA7.16.5 Construction Inspection for Wind Speed/Direction Responsive Control

Requirements for wind speed/direction responsive control are required in addition to requirements for VAV lab exhaust system with occupancy controls in NA7.16.1 and NA7.16.2 if the builder uses wind speed/direction responsive controls to meet fan system power consumption requirements.
Verify and document the following prior to functional testing:

(a) Wind speed and direction sensor is factory-calibrated (with calibration certificate) or field calibrated, as specified by Section 140.9(c)3C.

(b) The sensor is located in a location and at a height that is outside the wake region of nearby structures and experiences similar wind conditions to the free stream environment above the exhaust stacks as specified by Section 140.9(c)3C.

(c) The sensor is installed in close proximity to the fan that it will control so that it captures a representative wind speed/direction reading.

(d) The sensor is wired correctly to the controls to ensure proper control of volume flow rate.

(e) Wind speed/direction look-up table has been established and matches dispersion analysis results.

(f) Verify the methodology to measure volume flow rate:

Airflow sensor.
Static pressure as proxy.
Fan speed to volume flow rate curve.
Other.

(g) Confirm that design values on plans and specifications and measured values are within 10%:

Design inlet airflow rate of exhaust fan system (cfm).
Power of exhaust fan system at design conditions (watts).
Inlet airflow rate of exhaust fan system at occupied minimum acceptable airflow rate (cfm).
Power of exhaust fan system at occupied minimum acceptable airflow rate (watts).
Power of exhaust fan system at 60% of design exhaust fan system airflow rate (watts).
Calculate watts/cfm at maximum design conditions, Item (g)2 divided by item (g)1

(h) Measured occupied minimum acceptable exhaust fan system inlet airflow rate [item (g)3] is no greater than 60% of measured design exhaust fan system airflow rate [item(g)1].

(i) Measured exhaust fan system power at 60% of design fan system airflow rate [item (g)5] is no greater than 40% of measured exhaust fan system power at design exhaust fan system airflow rate [item (g)2].

NA7.16.6 Functional Testing for Wind Speed/Direction Responsive Control

Step 1: Simulate design conditions.

Record airflow rate at the stack (cfm).
Record airflow rate entering the exhaust fan system (cfm).
Record exhaust fan system power at maximum wind speed (watts).
Restore all curve points.

Step 2: Simulate the minimum occupied airflow rate by inducing a wind speed or overriding curve points.

Record airflow rate at the stack (cfm).
Record airflow rate entering the exhaust fan system (cfm).
Confirm that the airflow rate entering fan system airflow rate at minimum occupied conditions [Step 2(b)] is no greater than 60% of the exhaust fan system design airflow rate [Step 1(b)].

Step 3: Simulate the 60% of design airflow rate by inducing wind speed or overriding the curve points.

Record exhaust fan system power at 60% design airflow rate (watts).
Confirm that the fan system power at 60% design airflow rate [Step 3(a)] is no greater than 40% of the exhaust fan system airflow rate at maximum wind speed [Step 1(c)].
Restore all curve points.

NA7.16.7 Construction Inspection for Monitored Contaminant Control

Requirements for monitored contaminant control are required in addition to requirements for VAV lab exhaust system with occupancy controls in NA7.16.1 and NA7.16.2 if the builder uses monitored contaminant controls to meet fan system power consumption requirements.

Verify and document the following tests prior to functional testing:

(a) Contaminant sensor is factory-calibrated (with calibration certificate) or field calibrated, as specified by Section 140.9(c)3D.

(b) The sensor is located within each exhaust plenum as specified by Section 140.9(c)3D.

(c) The sensor is wired correctly to the controls to ensure proper control of volume flow rate.

(d) Contaminant concentration threshold has been established and matches dispersion analysis results.

(e) Verify the methodology to measure volume flow rate:

Airflow sensor
Static pressure as proxy
Fan speed to volume flow rate curve
Other

(f) If multiple sensors are present, ensure fan is controlled based on the highest concentration reading.

(g) Confirm that design values on plans and specifications and measured values are within 10%:

Design inlet airflow rate of exhaust fan system (cfm).
Power of exhaust fan system at design conditions (watts).
Inlet airflow rate of exhaust fan system at occupied minimum acceptable airflow rate (cfm).
Power of exhaust fan system at occupied minimum acceptable airflow rate (watts).
Power of exhaust fan system at 60% of design exhaust fan system airflow rate (watts).
Calculate watts/cfm at maximum design conditions, Item (g)2 divided by item (g)1.

(h) Measured occupied minimum acceptable exhaust fan system inlet airflow rate [item (g)3] is no greater than 60% of measured design exhaust fan system airflow rate [item(g)1].

(i) Measured exhaust fan system power at 60% of design fan system airflow rate [item (g)5] is no greater than 40% of measured exhaust fan system power at design exhaust fan system airflow rate [item (g)2].

NA7.16.8 Functional Testing for Monitored Contaminant Control

Step 1: Ensure no contaminant event is present. Simulate design conditions.

(a) Verify that the volume flow rate at the stack is at or above the minimum non-event value.

(b) Record airflow rate at the stack (cfm).

(c) Record airflow rate entering the exhaust fan system (cfm).

(d) Record exhaust fan system power at design conditions (watts).

Step 2: Simulate a contaminant event.

(a) Verify that the volume flow rate at the stack is at or above the minimum non-event value.

Step 3: Simulate the minimum occupied airflow rate.

a. Record airflow rate at the stack (cfm).

b. Record airflow rate entering the exhaust fan system (cfm).

c. Confirm that the airflow rate entering fan system airflow rate at minimum occupied conditions [Step 3(b)] is no greater than 60% of the exhaust fan system design airflow rate [Step 1(c)].

Step 4: Increase exhaust air demand at the lab spaces.

(a) Record airflow rate at the stack is at or above the minimum event value. (cfm).

(b) Record airflow rate entering the exhaust fan system (cfm).

(c) Confirm that the airflow rate entering fan system airflow rate at minimum occupied conditions [Step 3(b)] is no greater than 60% of the exhaust fan system design airflow rate [Step 1(c)].

Step 4: Simulate the 60% of design airflow rate.

(a) Record exhaust fan system power at 60% design airflow rate (watts).

(b) Confirm that the fan system power at 60% design airflow rate [Step 4(a)] is no greater than 40% of the exhaust fan system airflow rate at maximum wind speed [Step 1(d)].