When are Engineering Services Needed in Commercial Buildings?

Commercial buildings rely on various systems to operate correctly, and they include equipment such as lighting fixtures, air-handling units, compressors, boilers and pumps. To guarantee high performance and provide safety for occupants, the New York City Department of Buildings requires commercial buildings to meet a series of construction codes, as shown below:

Hiring the services of qualified engineers is the best way to ensure code compliance. In the case of new buildings and major renovations to existing ones, this is generally not an issue because code compliance is mandatory before the building can start operating. On the other hand, the systems in existing buildings can deteriorate over time, falling below the minimum standards established by applicable codes; the consequences of this can include decreased performance, higher operating and maintenance costs, and risky conditions for occupants.

Even if building systems are operating correctly, an assessment can help detect areas of opportunity to improve performance; the adage that says “if it ain’t broke don’t fix it” does not apply here, since technology is constantly evolving and there are always opportunities to enhance building systems.

1) Lighting Installations in Commercial Buildings

Lighting installations are among the most important systems in commercial buildings, for the simple reason that adequate visibility is necessary for commercial activity and human safety. The following are some common lighting issues that may diminish productivity and compromise safety, requiring the attention of an engineer:

Flickering Lamps – A flickering light source can be extremely distracting in commercial settings, causing visual fatigue as well. This issue tends to be more common with older fluorescent tubes powered with magnetic ballasts, although modern light sources can also be affected, especially if there are power quality issues. If your facility has flickering lamps, get them inspected by an engineer to determine the exact cause.
Humming – This can also cause distraction and is especially common with magnetic ballasts, which are used with HID bulbs and older fluorescent tubes. Humming and flickering often occur together.
Color Distortion – This typically signals issues with the ballast, so you should get an inspection if you notice changes in the color output of lighting fixtures. For example, metal halide lamps tend to look green when the capacitor in their ballast is deficient.
Frequent Lamp Failures – Lamps have a finite service life, but it is normally around 10,000 hours for MH and CFL bulbs, and around 20,000 hours for fluorescent tubes. If lamps are frequently burning it could mean you have power supply issues, and if it happens frequently in a specific fixture the ballast is most likely damaged.

Regardless of the issues in your lighting system, the best approach is to let a professional do the troubleshooting. Sometimes many factors interact with each other, and the relationship between them may not be evident.

Upgrading Lighting Installations

Of course, you can also get in touch with professionals if you want to upgrade your lighting system. In general, there are three types of improvements you can carry out:

Reducing energy consumption, which saves money by lowering power bills.
Improving the optical distribution and quality of lighting.
Making lighting smarter with sensors and automatic controls.

Of course, there are cases where all three upgrades can be carried out at once. Assume you have an installation with first-generation fluorescent tubes that are manually switched and directly visible. If this installation is upgraded with integral LED troffers controlled by occupancy sensors, all available benefits can be achieved simultaneously:

Saving money: Using LED fixtures reduces the input power, and using occupancy sensors reduces the total time the lights are on. For example, if you use fixtures that draw 50% less power and reduce their hours of use to 80% with automation, your energy consumption will only be 40% of what the original installation required.
Eliminating glare: The exposed fluorescent tubes are replaced with troffers that optimize lighting distribution. This makes indoor environments more appealing and enhances concentration.

In short, you should get in touch with an engineering professional or firm whenever you have lighting issues, or if you want to identify areas of opportunity to improve your current system. LED upgrades in New York City are normally eligible for rebates – make sure you don’t miss these cash incentives.

2) Commercial HVAC Systems

Heating, ventilation and air conditioning installations are among of the largest and most complex systems in commercial buildings. Their main purpose is to keep temperature and moisture within a range that is comfortable for humans, while constantly renewing the air inside the building; therefore, malfunctioning HVAC systems not only cause discomfort, but also degrade indoor air quality and may bring health issues. If any of the following conditions are found in a commercial building, getting in touch with an HVAC engineer or consulting company is recommended:

Inadequate indoor temperature.
Inadequate or fluctuating water temperature, in the case of water heating systems.
Excessive humidity or dryness: Both conditions are detrimental for comfort and health. Moisture also leads to mold formation, which degrades indoor air quality.
Drafty environment: Normally caused by inadequate duct or fan sizing, or a combination of both.
Noisy ducts: This condition often goes hand in hand with draftiness, and tends to have the same causes.
Unpleasant/combustion smells: Unpleasant smells generally indicate the ventilation system is not working properly; for example, negative pressure may draw in odors from service areas or from outdoors. If the smell of combustion gases is present, immediate attention is required even if there is no visible smoke – flue gases can be lethal in closed spaces.

Upgrading HVAC Installations

There is a broad range of potential upgrades that can be carried out for a commercial HVAC system, but this can also lead to confusion. However, you can determine what works best for your building with consulting services. The following are some common options:

Upgrading specific equipment: There are upgrades available for almost any piece of HVAC equipment. For example, a chiller and its cooling tower can be upgraded to more modern versions with variable speed control, enhanced efficiency and automation features.
Automation and control: There are occasions where the existing equipment offers high performance, but the full potential is not being achieved due to inadequate operation. In these cases, sensors and control devices can be added/upgraded, optimizing the HVAC installation in real time.
System-level upgrades: Sometimes the entire HVAC installation uses dated technology, and performance can be increased drastically by upgrading the entire system. The main drawback of this approach is that it can be very expensive; however, if a major renovation will be carried out soon, it is a great chance for a system-level HVAC upgrade. An example of a system-level HVAC upgrade would be to replace an old four-pipe installation with a variable refrigerant flow (VRF) or water-source heat pump system.

HVAC is normally the largest energy expense in a commercial building, sometimes exceeding all other energy expenses combined. Hence, upgrades that improve HVAC performance tend to be very attractive from the financial standpoint.

3) Pumping systems

High-rise commercial buildings normally use a pumping system because water from the local utility is unable to reach the higher levels with the pressure at which it is supplied. Pumps are also required for fire sprinkler systems, and for any HVAC configuration where water is used to carry heat.

There are two main conditions that can severely damage pumping system components: water hammer and cavitation. If they are not controlled, the service life of equipment is reduced drastically.

Water hammer or hydraulic shock occurs when the flow of water is forced to change direction or stop suddenly, causing pressure surges that propagate throughout the installation, potentially damaging equipment. Water hammer can be detected by the banging noise it produces, and valve failures may become frequent. It is possible to mitigate water hammer with damping measures such as pressure-relief tanks, or by controlling pump starts and stops so that there are no sudden variations in flow.
Cavitation occurs when water pressure becomes low enough for bubbles to form within the flow. These bubbles produce localized shockwaves as they collapse, and can potentially damage equipment. Pump impellers are particularly vulnerable to cavitation, since their blades cause a localized pressure drop as water speeds up around their edges.

If pumping system components fail frequently in a commercial building, these two factors are often the cause; the installation should be assessed by a qualified professional.

Improving Pumping System Performance

As with lighting and HVAC installations, there are plenty of energy-saving opportunities in pumping systems. The following are some commonly suggested measures:

Motor upgrades: Since pumps normally work with extended schedules, upgrading to a high-efficiency motor can yield an attractive return on investment.
Pump speed control: Pumping expenses can be reduced considerably if flow is modulated with a variable speed drive instead of valves.

Although pumps generally consume less energy than HVAC systems, their contribution to total energy expenses is significant nevertheless. Also, consider that pumping and HVAC systems often work together, for example in AC systems that use water-cooled chillers or water-source heat pumps. The two systems can achieve synergy if upgraded simultaneously.

4) General Building Improvements

When a commercial building has excessive energy expenses, upgrades to individual systems can help significantly, but to achieve the best result it is also necessary to upgrade the building itself. There are three main areas of opportunity in which an engineering professional or company can assist you.

Building Envelope Upgrades

The building envelope should accomplish three main functions:

Providing air-tightness, so that the only air entering and leaving the building is the air handled by the ventilation system.
Providing a thermal barrier between the building and its surroundings, keeping heat inside during the winter and outside during the summer.
Allowing sunlight to enter the building, but also minimizing the heat gain due to solar radiation.

Building envelope upgrades have the goal of improving performance in these three areas, but they can be very expensive. However, the net cost is reduced significantly when these measures are implemented during initial construction or during a major renovation.

Renewable Energy

Since energy is expensive in New York City, on-site generation with renewable energy systems can be an attractive option. The technologies with the most potential in commercial buildings are the following:

Solar photovoltaic arrays
Solar water heaters
Fuel cell systems
Geothermal heat pumps
Small-scale wind turbines
Biomass heating

Solar power might not seem attractive at first in New York, since the state is not one of the sunniest. However, there are so many tax incentives that they compensate the lack of sunlight. Combined with the high electricity rates, this turns solar power into a solid investment.

Building Management Systems

Energy-efficient appliances reduce total energy consumption, while renewable energy systems allow buildings to generate energy on-site. This can be complemented with building management systems (BMS), which can manage energy so that it is consumed when the cost of doing so is the lowest, without causing discomfort or inconvenience for occupants.

Utility companies bill higher rates when the grid is experiencing peak demand, but a BMS can monitor this and shift energy consumption away from those hours. This provides cash savings even if total consumption remains the same.
Commercial energy consumers are billed for individual peaks in demand, regardless of then they occur. A BMS can also mitigate or eliminate these peaks.
A BMS can decide the best way to use the output of renewable energy systems: Should it be sold to the utility, consumed immediately, or stored for later use?

Concluding Remarks

Commercial buildings can improve their performance significantly with an assessment by qualified engineers. It is possible to detect and fix issues affecting the existing installations, while finding areas of opportunity to save energy or improve comfort. The best results are achieved when building systems are addressed simultaneously, since it is possible to detect interactions among them, as well as opportunities for synergy.