Building readiness during epidemic period - By ASHRAE.org

Ashrae.org has just released the 2021 update for building readiness during the current COVID19 epidemic. Here We provide a summary and most important points to get your building ready in these tough times.
For the full document, please download it here

“The following Building Readiness information is meant to provide practical information and checklists for how your building should be operating and how to practically check its operation”

One of the most important features that must exist in such a system is the Secured Remote Access ability, Where the administrator can operate the system from anywhere and anytime. In case the existing system does not have such a method, the owner should coordinate with the building IT provider and BAS provider for secure remote access.

The Secure remote access method should provide the following: 

  • Cybersecurity must be put at the forefront of this endeavor as to not open the BAS and other building networks to
    unauthorized access.
  • If the BAS is not on its own Virtual Local Area Network (VLAN), consider segregating the building systems (BAS, Fire
    Alarm, Card Access, Cameras, etc.) into a VLAN to limit remote exposure to the building’s internal networks.
  • Consider two-step authentication as mandatory for remote access.
  • Care should be taken in granting editing access to the BAS to knowledgeable, trained operators only.
  • Set up user logging such that a virtual log of all changes are documented.

Making changes to accommodate epidemic responses:

  • After determining what sequence of operation changes are appropriate, make small changes to the
    the system at a time and monitor for a few days or through some varying weather conditions to make
    sure the system and building(s) are responding to the changes as expected.
  • Have the CxP or Control Contractor verify and document the effect of the changes through key
    trend reports and physical measurements or standalone data loggers.
  • Keep good records and document all meetings agreed to repairs, maintenance, and changes with
    written communication.
  • The team should consider making the changes to include an automated response such that you may
    return to the original sequences (or pre and post-pandemic sequences) at the push of the “virtual” button.
  • Care should be taken to limit access to the initiation of these automated sequences as they may
    have a large energy and comfort impact on your facility.
  • Existing alarm parameters may need to be adjusted during these new sequences as the original
    “normal” conditions may not be able to be met.
  • Ensure that this team follows the guidelines for the facilities’ Systems Manual later in this document.

 

Epidemic Conditions in Place

  • Ventilation per Code / Design
    • ASHRAE is indicating that the building systems need to be evaluated to confirm that the building’s
      HVAC systems are capable and operating to provide the code required or design levels of outdoor air
      when the building is occupied.
      The intent is to operate the systems in this manner when the building is occupied.
      Increasing outdoor air above code/design is considered a mitigation strategy to be evaluated.
  • Increased Ventilation above Code
    • One major concern is the ability to maintain space conditions. Hot and humid climates could struggle to keep the space
      below acceptable temperature and relative humidity for comfort. Cold climates could struggle to keep the space above
      acceptable space temperature and relative humidity for comfort. It is important to note that research indicates that
      maintaining the space relative humidity between 40% and 60% decreases the bio-burden of infectious particles in the space
      and decreases the infectivity of many viruses in the air. The team should consider adjusting the space comfort setpoints to
      increase the system’s ability to use more outside air.
  • Building and Space Pressure:
    • Building and space pressurization is another important consideration.
      Care should be taken when increasing outside air but keeping exhausted and relief air systems as designed. New
      problems can be created such as:
      • Doors that will not close
      • Excessive noise at entrance doors and between adjacent spaces
      • Access/egress issues at common hallways or egress points (in extreme conditions)
      • Reverse of the intended pressure required for space
      Excessive building pressurization can also affect vertical transportation systems and areas that are intended to
      be negatively pressurized, such as commercial kitchens, bathrooms, process areas, and custodial areas.
      It is very important that these overall building systems are evaluated by a qualified TAB firm, Cx provider or
      design professional to ensure that the modifications for pandemic safety do not create additional issues.
  • Pre- or Post- Occupancy Flushing Strategy:
    • The intent is to ensure that while the building is operating, your ventilation schedule should assist in removing
      bioburden during, pre-, or post-occupancy of the building. Flush the building for a duration sufficient to reduce
      the concentration of airborne infectious particles by 95%. For a well-mixed space, this would require 3 changes of
      building volume using outdoor air (or equivalent outdoor air including the effect of filtration and air cleaners) as
      detailed in the calculation methodology.
      In lieu of calculating the air change rate, pre-or post-occupancy flushing periods of 4 hours may be used since
      this should be sufficient for most systems meeting minimum ventilation standards.
      So for each mode, the control would be as follows:
      • Occupied: bring in the code/design outdoor air per system.
      • Pre- or Post-: The general method is to operate the systems in Occupied Mode for “x” hours prior to, or after,
      daily occupancy. Use the calculation to determine “x”.
  • Flushing Air Changes Calculations for Well Mixed Spaces:
    • The flushing process is intended to be for removing gases in a well-mixed space.
    • It is good for removing VOC’s, CO2, and anything contaminant that approximate gases.
    • While all gases can be assumed with good science to be evenly distributed in space,
      particles may not. Airborne particles cannot be treated as gases and these particles follow
      relaxation theory and move on air currents, some unknown percentage of particles may go
      back to the return and likely do.
    • The entire principles that this section is based on is delivering viral load particulate
      reduction to the space diluting the clean air-breathing zone.
  • Upgrading & Improving Filtration:
    • Building owners are encouraged to improve the efficiency of the filters serving their HVAC systems within the
      guidance provided for most of the building types listed on the ASHRAE COVID-19 Preparedness Resources
      website. Mechanical filters are the most common types of filters found in HVAC systems. The term used to describe mechanical filter efficiency
      is MERV which is an acronym for Minimum Efficiency Reporting Value (mechanical filter definition also includes
      filters that have a static electrical charge applied to media prior to use). The MERV rating of a mechanical filter is
      determined by filter manufacturers in accordance with ASHRAE Standard 52.2 – Method of Testing General
      Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size. Standard 52.2, table 12-1 lists filter
      MERV rating parameters for MERV 1 through MERV 16. The higher the MERV number the better the ability of a
      filter to remove particles from the air ranging in sizes from 0.3-micron diameter up to 10 microns in diameter at
      standard airflow conditions and face velocities specified in the test standard.