If you have commercial tenants, they’ve likely scheduled heating or air conditioning outside of your building’s usual business hours. Managers and owners commonly refer to these extra hours as overtime HVAC, after-hours HVAC, after-hours air conditioning or some variation. These overtime utility services give companies the flexibility to host special events, hold annual meetings, or simply extend their workday hours.
Tenant overtime HVAC systems are online platforms that automate the scheduling and billing of those after-hours HVAC requests. These systems streamline much of the traditional steps of a tenant overtime program, including scheduling and billing. Consequently, they save property managers and their staff time and resources. In addition, overtime HVAC systems can increase tenant satisfaction and conserve energy. Modern systems operate on a software-as-a-service model (SaaS) where property managers pay a monthly subscription for the service, but one-time fees are also available.
Modern tenant overtime systems let property owners set normal business hours (blue), while tenants can schedule HVAC service outside these times (green).
After-Hours vs Standard Occupancy Times
Standard business hours or “occupancy times” for buildings vary by region, but most fall somewhere around 8 a.m. and 6 p.m. Monday to Friday. Owners and managers define their business hours within commercial leases and agree to provide heating, cooling and lighting for tenants to operate their businesses. However, many leases also allow for “after-hours” or “overtime” HVAC requests. These are defined as any times outside normal business hours, and they’re usually billed separately from normal OPEX.
To recoup the costs for providing after-hours HVAC services, managers and owners usually charge tenants a fixed hourly rate (ex: $35/hour). The rate usually includes an estimated energy cost for providing service for one hour, plus an admin fee to cover staff time.
Overtime HVAC Scheduling
Because after-hours HVAC requests are outside standard operating hours, tenants must schedule them with the manager or building engineer. Typical steps in a standard overtime program usually involve the following:
The tenant makes an overtime HVAC request via email or text.
The manager records the request in a spreadsheet and notifies the building engineer.
The engineer programs the request into the building’s BMS.
The manager invoices the tenant at the end of the month for the overtime charges.
Managing this process requires time and resources, which is why most leases require a 24 or 48-hour notice per request. The window gives staff enough time to schedule the request, but places limits on how spontaneous tenants can be with last minute schedules.
Tenant overtime HVAC systems eliminate or simplify many of the above steps. Instead of an email or phone call, tenants use an online portal and web browser to submit overtime requests. Since overtime systems link to your building’s BMS, they bypass the need for manual reporting and system programming—no managers or engineers needed. This keeps notice times shorter, and tenants benefit from the increased flexibility.
Overtime HVAC systems also come with mobile apps. Tenants use these programs to schedule after-hours services from their smartphones or tablets. The freedom of mobile scheduling tends to increase overall tenant satisfaction with a property’s after-hours program.
Common connection flow of a cloud-based tenant overtime HVAC system to a commercial property.
Overtime HVAC Billing
Billing for standard hour energy is straightforward. Tenants pay pro rata based on the building’s total utility costs for the month. The strategy essentially splits the energy costs among all tenants equally, and everyone pays their share at the end of the month. However, overtime HVAC charges add complexity to monthly billing. It would be unfair to split overtime energy costs among all tenants, since only specific ones use it, so landlords invoice tenants only for the kWh they use.
However, individual invoicing takes more time. Spreadsheets need updated. Invoices generated. Emails sent to tenants. Plus, manual entry increases the risk of mistakes, leaving tenants paying too much or too little. Tenant overtime HVAC systems automate most of these monthly billing tasks, eliminating human error and tenant disputes around charges.
Overtime systems record BMS operation histories in their servers. So, times, days, and durations of overtime services are automatically generated for any timeframe. Most platforms also automate monthly billing to tenants. Since the system tracks individual usage, it can email automated invoices to tenants, taking the paperwork off property managers.
Energy Conservation
On average, 30% of the energy used in commercial buildings is wasted. After-hour scheduling changes and cancellations happen. It’s not uncommon for tenants to walk into unheated boardrooms or for entire building floors to sit unoccupied while chillers run at full power. Such scheduling mistakes waste energy and money. The bulk of these issues stem from recording mistakes and human error. A work order was overlooked, an email went to spam. Someone was out sick. These are common, often unavoidable, situations.
Because they’re automated systems, tenant overtime platforms eliminate human error. Schedule changes and cancellations are caught more frequently and wasted energy reduced.
Overtime HVAC systems can also positively affect tenant attitudes toward energy waste. Because tenants pay for the overtime kilowatts they use, they’re more cautious about waste. In contrast, attitudes towards energy use during standard business hours can be markedly different. Those tenants often have a “use it or lose it” approach, feeling they should condition the air in their spaces, whether they’re empty or occupied. The attitude is “We’re paying for it anyway.”
Tenant Satisfaction
Aside from time and money savings, the biggest selling point of overtime HVAC systems is their value to tenant businesses. With HVAC scheduling, office managers can operate hybrid workspaces more effectively. Government agencies can use after-hours reports to report on sustainability goals. Software developers could employ overtime usage to evaluate team productivity. Marketing agencies could add overtime energy costs as a billable line item for clients. The value of tenant overtime HVAC systems is yet to be fully realized, but the heart of it lies in their ability to empower tenants to run better businesses and organisations.
Successful properties have lighting that suits the needs of their occupants. Proper lighting can boost productivity, mood and an overall sense of worker wellbeing. While bad lighting can do the opposite. Light flicker is detrimental to the workplace, often causing migraine headaches, eye strain and general eye discomfort in workers. Even worse, light flicker can often be a hidden danger, going unnoticed for months or years while negatively affecting occupants. Understanding and detecting light flicker ensures a healthy and safe working environment.
What is Light Flicker?
Light flicker is the repetitive and rapid changing of a light brightness over time. Such light repetitions are too fast for most humans to see but can still produce negative side effects in individuals with sensitivities, including headaches, nausea and eye strain.
Lights flicker because of their power source. Most facility light sources run on alternating current (AC) electricity. AC produces electrical cycles that fluctuate from positive to negative. Power starts at zero, grows to a maximum positive charge, then reverses itself to a maximum negative charge. These cycles are measured in hertz, and most power is delivered in 50 or 60 hertz.
Because most industrial and commercial lighting runs on AC current, their bulbs must also follow a similar alternating cycle. Illustration 1 shows the alternating waveform of a standard incandescent bulb. The bulb cycles through a maximum positive charge to a maximum negative charge. Essentially, the AC power supply is turning the incandescent bulb on and off.
However, as the bulb’s cycle moves from one maximum charge to another, it passes through a lower voltage. Therefore, the bulb goes from bright to dim to bright again. It’s these repetitions that cause light flicker.
Illustration 1. The typical alternating voltage waveform for an incandescent bulb. These changes in voltage are why light flicker happens.
We normally don’t notice light flicker because of the speed at which it occurs. Lights reach maximum brightness twice in each cycle, so at 60 hertz power, that’s 120 cycles or 120 times per second! At that speed, the light appears to be “on” all the time. This is why turning (slowing) down an incandescent bulb using a dimmer switch can produce a visible flicker.
Ways to Detect Light Flicker
To eliminate light flicker, first you must locate it. The easiest place to start is your “Suggestion Box” or tenant satisfaction survey. Are you getting complaints about the lighting? You may have a big problem, even if it’s only a small group of respondents. Remember: not everyone is susceptible to light flicker effects, so don’t let “only a few complaints” lull you into a false sense of security.
If you do suspect there’s a problem, go through and test suspected areas of your building. The easiest way to detect light flicker is to take a photo of a fast-moving object. Snap a photo with your smartphone of an object like a ruler (see Photo 1 below). If you can see discrete positions of the ruler (left), the lighting has a high light flicker. But, if the position blurs together (right), it has a low light flicker.
Photo 1: The stepped appearance of the waving ruler on the left photo indicates high flicker rate in a bulb, while the blurred left image indicates a bulb with less flicker. Photo courtesy of Susan Mander.
Another strategy for testing for light flicker is to use your smartphone’s camera app. Most people have at one time or another witnessed dark horizontal bars appear on their phone’s screen when they view light sources such as LED bulbs, computer monitors or TVs. These horizontal bars form because the camera’s video frame rate and/or screen refresh rate is high enough to capture the source’s dimming light cycles.
To test a bulb for flicker using your phone, take a photo of the light source, a “slow mo” video or simply hold the phone close to the source while viewing a live image. If there are horizontal bands of dark bars, there is light flicker (Photo 2).
Photo 2: Slow motion video reveals dark horizontal bars across a light source like an LED bulb or computer monitor. Photo courtesy of Susan Mander.
Reducing the Effects of Light Flicker
You can combat light flicker with natural light. Since light flicker exists because of the fluctuation from bright to dim, you can use natural lighting, which has zero flicker, to fill in the gaps. While sunlight isn’t a substitute for quality bulbs and proper electrical system upkeep, it can be a good short-term solution. What’s more, natural lighting has other benefits to the physical and mental health of workers.
Fluorescent Bulbs
Early in their development, gas-filled linear fluorescent bulbs were notorious for producing light flicker in office buildings. Early models caused worker headaches and eye strain, but the later switch from magnetic to electronic ballasts eliminated the flicker along with the complaints.
Today, linear fluorescents and their small cousins the compact fluorescent bulb (CFL) enjoy widespread use. However, fluorescent lights can still produce light flicker for a variety of reasons.
Like any bulb, these gas-filled illuminators work less effectively with age. And, unlike incandescents, they don’t suffer catastrophic failure. That is, fluorescents won’t simply go out. Instead, they will continue to work even if only way. That means flickering side effects could go on for some time. So keep fluorescent bulbs fresh. If replacements are still flickering, you may have a bad ballast, especially if you hear a hum.
LED Bulbs
LED bulbs are the growing trend in facility illumination because they’re more efficient than incandescents and fluorescents. LEDs also extend bulb life, with a run time of around 20K to 100K hours.
Instead of tungsten filaments and gas vapor, LEDs use electronics (light emitting diodes) to produce light. Because of this, they tend to have a harsher AC flicker wave profile than other bulb types. So, bulb designers attach electrical components in the LED bulb’s base to reduce flicker.
However, when it comes to light flicker and LEDs, it’s a buyer beware situation. You usually get what you pay for. Some LEDs have almost no flicker, while others have an abundance. It all depends on the quality of their electronics. Perform your own flicker detection tests before you decide.
Mander, Susan. “Key Lighting Principles for Facilities Managers.” Presented 15 June 2021. Online presentation for Facilities Managers Association of New Zealand.
Are you finding it hard to procure office equipment? Is your supply closet running short on toilet paper? Supply chain issues are a global problem, and shortages are hitting every sector. Office managers in the U.S. are finding it hard to locate basic office supplies like paper, printer ink, lightbulbs and, yes, even toilet paper.
Trade experts say the global supply chain conundrum could be years away from resolving itself. So, many firms will need to adjust their procurement practices to locate alternative resources and manage rising costs. To that end, here are five tips for surviving the supply chain issues you’ll want to try out this year.
1. Barter with Competitors
Supply issues are prime times for beefing up your business relationships or calling in old favors. If you have excess resources, find a competing property owner who needs them and offer a trade. Such transactions could also include services-for-supplies too. Don’t be too proud. Cooperation helps the whole industry win. NOTE: Depending on where you do business, you may be required to report such bartering “profits” as taxable income. Check with your CPA.
2. Buy Used, Source Local
With international supply chains still struggling, many are looking to local and/or second-hand stores for procuring used supplies like office equipment or furniture. Look at both brick-and-mortar and online stores. On trading platforms like Craigslist, eBay or TradeMe you can easily filter searches by location to find products/services within a workable range for quick delivery. Buying used cuts down delivery time and gets the job done until you can find replacements. It’s also better for the environment!
3. Reduce Your Use
One upside to doing without is learning to live with less. Supply shortages are great opportunities to launch campaigns around efficiency and cost cutting. Use less paper products by transitioning to digital documents. Is your disposable coffee cup supply running low in the break room? Then buy your staff personlised mugs. Necessity is the mother of Invention, so use an unpredictable situation to promote conservation and frugality among your team and tenants.
4. Promote Flexible or Remote Working
By embracing the remote work trend, you can offset some supply use and costs to workers, many of whom will be happy to trade sweatpants and a much shorter commute. Besides using fewer resources, flexible work models offer more benefits for both employees and companies including increased productivity and higher retention.
5. Prepare for Tenant Backlash
Lack of supplies inevitably trickles down to your tenants. Sidestep complaints and backlash by preparing them before scarcity hits. Here are a few themes to weave into your tenant messaging.
Fairness. Some tenants may feel others are getting preferential treatment. Strong messaging is needed here. Any emails or correspondence needs to firmly dispense with such rumors before they grow. Maintain a voice of empathy and understanding around the shortages and their implications.
Transparency. Keep tenants abreast of delivery updates. Being in the dark is worse. When tenants can see there’s an end in sight, their patience increases dramatically. But even if you have no idea, be honest about your situation; sincerity does the heavy lifting when it comes to acceptance of a bad situation.
Collective Struggle. Take a “We’re in this together” approach. Groups get through things easier when there’s a feeling that everyone is sacrificing. However, this isn’t a time to point out how you’re the victim too; don’t unwittingly create a competition for “who’s got it worse.” Instead, stress collective sacrifice as a balm for individual angst and impatience.
Fire protection systems are one of the most complex and ubiquitous structures within facilities today. They contain many parts intertwined with other building components. For example, emergency lighting and smoke detectors wire into your electrical system. Fire pumps and hydrants hook up to your water mains. Fire alarms connect to your building’s access system to automatically unlock exterior doors.
Your HVAC system is also closely coupled to your fire protection equipment, and its maintenance and condition can directly impact the safety of your inhabitants and the extent of damage to your property.
1. Ductwork
Your system’s ductwork distributes conditioned air throughout the building. But during a fire, such distribution is unwanted. As temps rise and smoke builds, your HVAC’s return ductwork can carry smoke, toxic gases, and superheated air throughout other areas. This spreads the fire and puts occupants in danger. Even worse, supply side ductwork can actually “feed” a localised fire with fresh oxygen, increasing the temperature and property damage.
During a fire, smoke is the number one killer. In fact, most fire deaths are not caused by burns, but by smoke inhalation. Therefore, controlling its spread is safety 101. Plus, smoke can often emit from sources besides an open flame. Burnt toast or microwave popcorn could result in smoke rolling through an entire office floor. This could cause a panic and dangerous stampede to exits. So, any fire safety plan should also include the perception of fire itself as a real threat to life and property.
Duct smoke detectors can help. These devices reside within your ductwork where they detect smoke moving throughout your HVAC system and initiate pre-programmed actions. For example, one of your HVAC fan motors overheats and produces smoke. Once activated, the duct detector could turn on an exhaust fan, close a damper, shut down automation systems, signal an alarm and/or cut power to the fan motor itself.
2. Fire and Smoke Dampers
Fire dampers are another critical way your HVAC systems aid your facility’s fire protection system. Dampers are essentially air valves that shut off airflow in the event of a fire. They’re normally installed at any point where your system’s ductwork passes through a wall, floor or other fire-rated partition. The idea is to close off HVAC ventilation for any area where a fire exists. So, locating them within a fire-rated wall, for example, retains the integrity of the wall even if the ductwork falls away or is damaged by fire.
There are two basic types of dampers: fire and smoke. Fire dampers are usually triggered by a physical device such as a fusible link. Once the temperature rises above a specific point, the fusible link will melt and trigger the closing of the fire damper. As its name suggests, the damper’s main function is to stop fire from spreading through the ductwork.
Smoke dampers are part of the smoke suppression system. They typically connect to fire alarm systems, which trigger the dampers to close and prevent smoke transference. There are smoke/fire combination dampers as well.
Most fire codes require fire and smoke dampers to be actuated and tested every few years, depending on the facility type. Make sure you know your fire code and test that your dampers are physically working, installations are compliant and any replacements are compatible with your system.
3. AHU Support and Location
In the event of a fire, your alarm system should shut down any air handling units (AHUs) within the affected area or site wide. Again, the purpose is to contain the movement of smoke and air, and your AHU is the central place where this happens. However, operation isn’t the only consideration.
AHUs are large, heavy pieces of equipment weighing several tons depending on the size of the system. They’re also loud; that’s why they’re usually located within mechanical rooms and building rooftops. In multi-storey properties, these behemoths can become a danger to building inhabitants. During a fire, walls and floors weaken under intense heat, and those supporting heavy AHUs can give way quickly. While there’s little you can do to predict heat intensity during a fire, you can ensure your AHUs are appropriately located and that building floors are rated for their weight and size.
Conclusion
To function correctly, building systems must work together. It’s not enough just to tackle preventative maintenance for one system and ignore another. Their intertwining requires awareness of how changing one system affects another. Your HVAC system is no different. Upkeep and maintenance of it directly affects the effectiveness and efficiency of your fire protection system.
The COVID pandemic increased awareness and use of relatively new decontamination methods for medical facilities. In addition to standard surface cleaning and disinfection, hospital managers employ vaporized hydrogen peroxide (VHP) systems within negative pressure rooms to eliminate SARS-CoV-2. Sometimes referred to as “Deprox,” these systems distribute a mixture of hydrogen peroxide and water within a room. The mixture is small enough to decontaminate areas that are too difficult or impossible to clean by hand.
However, VHPs must work in conjunction with HVAC systems to be safe and effective, and most functional descriptions put strict limits on an HVAC’s operation during decontamination. Use the following information to guide your design when connecting to VHPs.
HP Vapor vs Aerosol Systems
There are two methods for dispersing hydrogen peroxide (H2O2) for airborne disinfection. One is vapor phase hydrogen peroxide (VPHP) and the other is aerosolised hydrogen peroxide (aHP). The main difference being the size and concentration of the hydrogen peroxide as it leaves the system. VPHP systems produce much smaller particles and at higher concentration than aHPs. They are much closer to a gas than aHPs, which are more of a “fog” ranging from 5 and 20 μm in size.
Exposure Limits
Both VPHPs or aHPs require some downtime for operation and room exposure levels to return to normal. Decontamination cycles may take up to three hours to complete. Exposure to hydrogen peroxide vapor can be harmful, resulting in irritation to the eyes, nose and throat. The OSHA standard for permissible exposure limits to H2O2 is 1 part per million parts of air (ppm) averaged over an eight-hour work shift.
Functional Descriptions
Include these sections when writing a FD that includes VPHP or aHP for negative/positive pressure rooms.
Room Modes—Room modes include isolation, deprox and standby. During the deprox process, the HVAC system should be turned off and dampers closed to ensure the VHP system works effectively.
Closing Dampers—When switching from standby or isolation to deprox mode, factor in a lag time to allow dampers to fully close. For example:
If the room is switched to deprox mode, the deprox LED will flash on and off for 75 seconds whilst the room dampers are driving closed. Once the 75 seconds have passed, the LED will be enabled.
Velocity Pressure Setpoint—Include a deprox pressure setpoint when setting duct velocity pressure points.
If the room is put into deprox mode, the velocity pressure setpoint is reduced to the deprox velocity pressure setpoint (To be determined at time of commissioning).
Smoke and Fire Detectors
Particles from VPHP or aHP can set off fire and smoke detectors. Consider the implications for your HVAC system. Since HVAC systems are normally integrated into fire systems to ensure proper exhaust of smoke, a false alarm may affect your system.
