EBOM 2009 IEQc2.3: Occupant Comfort—Thermal Comfort Monitoring

Sonrisa, I believe that either device (an infrared thermometer or a black globe thermometer) would be acceptable to take periodic radiant temperature readings. I could be wrong, but I don't think ASHRAE 55 excludes the use of infrared thermometers. Honestly, when LEED User was being built, we may have just had a better photo of an infrared thermometer to put on this page.

As far as the testing schedule, you don't have to hit on a perfect design day, but GBCI will want to see that you are being thoughtfull about scheduling the testing in an appropriate time of the year.

ASHRAE 55 does not require a specific device, but requires you to measure mean radiant temperature (MRT).

Neither globe thermometers nor infrared thermometers measure MRT, but both produce results that can be converted to mean radiant temperature. The two technologies would just require different equations to convert the measurements.

Globe thermometers are more common since they only require one measurement to determine mean radiant temperature. Their measurement can be converted to MRT via Equation 11 on page 14.29 of ASHRAE Fundamentals 2005.

Infrared thermometers will require at least six measurements for each point (top, bottom, four sides) which can be converted to MRT via Equation 50 on page 8.10 of ASHRAE Fundamentals 2005.

Humidity sensors are not necessarily inaccurate but they do require frequent calibration to be useful.

They are more useful where humidity is being controlled but humidity is a significant contributor to thermal comfort and that is why they are required. One could certainly make the case that they only make sense in a retrofit if they regulate humidity.

Melissa, installing sensors as you describe should meet the requirements, but you do also need to track the data generated and make sure thhat you're meeting relevant comfort criteriaComfort criteria are specific design conditions that take into account temperature, humidity, air speed, outdoor temperature, outdoor humidity, seasonal clothing, and expected activity. (ASHRAE 55–2004).

Hello Wendy

- I certainly think you can exclude the restaurants if they are less than 10% of building square footage. They seem to fit the requirements for the exemption in every meaningful way.

- You are correct that EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. requires only 1 sensor per humidity zone. However, rather than a random sampling, I would point to the language that encourages placing sensors in such a was so as to ensure they are 'representative of conditions'. This is not the most direct guidance, but I think it reflects the interest in placing sensors where they will give you the most relevant and useful information about humidity levels, as opposed to simply slapping one on a wall somewhere in the zone. Also, in terms of guiding the number of sensors, note that the Reference Guide acknowledges that the number of humidity sensors may be fewer than temperature sensors - this implicitly suggests that a guide to your starting point for the number of humidity sensors should be the number of temperature sensors. If those are somewhat consistent, I would think you're in good shape.

- I think that's a safe bet. Clearly a restroom with showers is in a class by itself. I assume that any restroom is likely to have higher general humidity levels than office space, but I would suspect the difference is marginal.

Hope that helps a little,

Dan

As stated, there must be at least one air temperature sensor located in each HVAC zone. As the intent is to provide a comfortable thermal environment, each occupied space should have some degree of monitoring. As stated in the LRG, pg. 405, "...if space uses and configurations make it likely that a single measurement point is not representative..." additional sensor would be required.

A 4 story building with only two temperature sensors, in my mind, would not meet the requirements. It would be unlikely that thermal comfort would be met in all occupied areas by all occupants.

I am still trying to figure this one out and really need clarification. The bigger picture is that I have a four story 486,000 square foot building split up into 6 "Cores". Each core has it's own air handler that is controlled by the BAS. Each core has temperature sensors on the 1st and 4th floor that send signals to the BAS to control supply air temperatures. Conditioned air is controlled, monitored, and provided to terminal boxes throughout the core. Each terminal box is controlled by a pneumatic thermostat for occupant comfort. Since we have pneumatic thermostats they do not report to the BAS but still provide the occupants a way to control space temperatures.

The recommendation above in the Before the Performance Period section says - "Make sure that there is at least one air temperature sensor located in each HVAC zone." Please define HVAC ZONE in this case.

In the larger picture, we contol and track supply air temperatures throughout each core of the building with our BAS. If you can extend the definition of a "Zone" in this case to correspond to our "Core" we feel comfortable that we meet the intent to provide, monitor, and track conditioned air in occupant spaces.

If "Zone" is defined as an area controlled by an individual thermostat then this credit becomes much more unreasonable and unobtainable. We have over 600 thermostats in the building! I feel it would be very wasteful to remove/replace/retrofit all the terminal boxes and thermostats to expensive DDC controls required to have each thermostat report to the BAS.

We have an excellent Energy Star score and our building engineers are constantly monitoring the BAS to make sure our occupants are comfortable. This is my first experience with a LEED EB project and really need help understanding and meeting the intent of this credit.

We have a 5 story multi-tenant office building and discussed with our engineer about defining HVAC zones. We believe the definition of a kitchen requires an exhaust fan so we have ruled all tenant kitchen/break rooms as still office space since they only include sinks, coffee machines...

We therefore will survey conditions throughout each floor and provide evidence as to why we are only using 5 (1 per floor) humidity sensors - assuming that our readings provide the evidence that humidity acorss the floor are same/consistent and there is no need to add additional sensors beyond one per floor.

David,

If each "core" is served by its own AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork., and the conditioned air from each core is controlled, monitored, and provided to terminal boxes throughout the core, then it would appear to be on the right path.

If understand this correctly, you have six cores running (vertically) through the bldg with air supplied by AHUs. The cores are tapped into by supply ducts at each floor level that serve termination boxes at various locations around the floors?

But please clarify for me: If it is the case that each core has temperature sensors on the 1st and 4th floor that send signals to the BAS to control supply air temperature, what happens on the 2nd and 3rd floors?

Thank you John. You do understand correctly on the supply ducts. They serve termination boxes at the various locations.

On the floor sensors, the BAS averages the temperatures for the 2nd and 3rd floor to adjust air temperatures. Is this acceptable?

David,

In my mind, the goal is to provide a comfortable thermal environment in all of the occupied spacesOccupied Spaces are defined as enclosed spaces that can accommodate human activities. Occupied spaces are further classified as regularly occupied or non-regularly occupied spaces based on the duration of the occupancy, individual or multi-occupant based on the quantity of occupants, and densely or non-densely occupied spaces based upon the concentration of occupants in the space. and to do this, the credit requires continuous monitoring of, at a minimum, air temperature and humidity in occupied spaces - that is, at least one air temperature sensor must be located in each HVAC zone. That being said, even though the "cores" might be within range, how does the BAS/managers know if the appropriate temps and humidity levels are being met in the actual occupied areas?

But, now, you got me thinking more. And I could be overthinking it. Do the termination boxes at the end of the supply ducts change the air temperature (warmer/cooler) and, consequently, the humidity?

I could add temperature sensors to each floor to provide continuous monitoring of temperatures. Humidity sensors would be added to defined humidity zones (kitchens, locker rooms, etc.)

The terminal boxes supply heated or cooled air at a temperature determined by the BAS to the occupied space until the individual thermostats are satisified.

This would be much easier to accomplish with a DDC system. However, the challenge of an Existing building is to provide comfort with the equipment we have. A DDC system with individual thermostat control/monitoring is just not economical to install in this large a facility. If a DDC system is the only way to achieve this credit it is just not possible and puts Existing Buildings at a disadvantage.

I think we are very close to achieving the intent of the credit. I appreciate your help in getting us farther along to obtain our goal. Let me know if you have additional comments or questions.

Thanks!

For this credit, absolutely not. You simply need to measure humidity levels. Please see the detailed information on the requirements above in the credit language and Checklists tabs. (Paid membership required to see that content—and highly recommended.)