The stakes are higher when designing HVAC and plumbing systems near the ocean. Salt-laden air, high humidity, and corrosive conditions can significantly reduce the lifespan and performance of mechanical equipment and fixtures. Whether you’re working on a marine research facility, a waterfront national park, or a retail store with water views, understanding how to protect your HVAC systems in these environments is essential.
Why Marine Environments Are So Challenging
Salt in the air accelerates corrosion, especially on exposed metal components like condenser coils, piping, and ductwork. Over time, this can lead to:
Reduced heat transfer efficiency
Increased maintenance costs
Shortened equipment lifespan
Equipment failure
HVAC Equipment Coil Protection
When you are near the ocean, protecting your condenser and/or evaporator coil is essential to ensuring the longevity of your equipment. Without this, corrosion can occur at your coils, reducing the equipment’s lifespan.
Location Matters:
Within 3–5 miles of the ocean: Your outdoor condenser coil should have a salt-spray rating that meets ASTM B117 standards.
Within 1 mile of the ocean: Both the condenser and evaporator coils should have a salt-spray rating that meets ASTM B117 standards.
This salt-spray coating can either be factory applied or applied by a third-party provider. This should be coordinated with the equipment manufacturer to ensure the final requirements can be reflected in your drawings.
Material Selection
Beyond coils, all exposed materials should be chosen for their resistance to corrosion:
Piping: Use corrosion-resistant materials or coatings such as PVC or type 316 Stainless steel.
Ductwork: Type 316 stainless steel may be necessary depending on the amount of exposure to salt-laden air.
Outdoor Fixtures: Hose bibbs, wall hydrants, and other plumbing fixtures on the exterior of the building should be marine-grade.
Drainage Systems: If saltwater is expected to enter drains (e.g., from rinsing equipment), ensure the drain materials are properly specified for this marine grade application.
Confirm if sand will be a concern in the space and if sand interceptors should be considered on certain drain lines.
Pro Tips for Marine HVAC Design
Consult with manufacturers early to confirm coating options and any performance derates.
Specify coatings clearly in your documentation—don’t assume they are standard.
Plan for maintenance: Regular inspections and cleaning are essential in salty environments, even with coatings.
Educate your clients about the importance of these upgrades. They may cost more upfront but save significantly in the long run.
Designing HVAC systems for marine environments isn’t just about resisting rust—it’s about ensuring long-term performance, reliability, and safety. By specifying the right coatings, materials, and installation practices, you can protect your systems from the harshest coastal conditions.
Working on a coastal project? We can help. Click below or email Stacey Richardson at srichardson@360eng.com to get started.
360 Engineering, a full-service mechanical engineering firm founded in 2003 by Denise Dihle and working on projects of all sizes in Colorado and across the U.S., has announced that the firm’s senior leadership team has joined Dihle as equity partners. The senior leadership team is comprised of Melissa Kisicki, CDFA, Stacey Richardson, CPSM, Spencer Rioux, PE, Brennen Guy, PE, and Lexie Zimmerman, PE. The move reflects 360 Engineering’s long-standing commitment to growing from within, ensuring continuity for the firm’s clients, and building a strong future grounded in shared vision and values.
“I established 360 Engineering as a firm that would be able to provide customized engineering solutions and personalized customer service to all our clients, and that will continue to be the case as this outstanding and highly respected team of professionals join me as equity partners,” said Dihle who has been recognized by industry organizations, peers and clients as a progressive leader in mechanical engineering, design and construction administration throughout her 30-plus year career. “These individuals have worked side by side with me and our entire team for years and promise to maintain the trust and results 360 Engineering has achieved with our clients. It’s an exciting time as we continue to look forward to delivering the same outstanding results on behalf of the companies and projects we represent.”
360 Engineering will maintain the firm’s SBE/MWBE (Small Business/Woman-Owned Business) status. Dihle will continue in her role as president and principal-in-charge.
The senior leadership team’s deeper investment in the firm after years of service signals not just confidence in where 360 Engineering is going, but a commitment to the people and partnerships that have been integral to the firm’s growth and success.
“Our clients’ experience with 360 Engineering remains unchanged and grounded in the same values, quality, and reliability they’ve always trusted,” continued Dihle. “We look forward to continuing in our status as an award-winning, locally and nationally recognized Woman-Owned Small Business. We’re excited about what the future holds and deeply grateful for the continued trust of our clients and colleagues.”
When it comes to HVAC design, humid climates present unique challenges that require thoughtful planning and precise execution. Whether you are working in coastal regions or cities with high summer humidity, understanding how to manage moisture is critical for comfort, efficiency, and building longevity. In this post, we’ll explore essential considerations for designing HVAC systems in humid environments.
Equipment Sizing
In humid climates, your cooling coil must do double duty—cooling the air and removing moisture. This means:
Psychrometric calculations are essential to size your cooling coil correctly.
The coil must reach saturation to allow condensation and effective dehumidification.
Right-sizing your equipment is essential. Oversizing equipment can lead to short cycling and poor humidity control.
Consider hot gas reheat if your DX system lacks staging capabilities.
Always ensure the building is positively pressurized to prevent humid air infiltration.
Air Distribution
Poor air distribution can lead to condensation and comfort issues. Keep these tips in mind:
Don’t supply air directly above exterior doors. Humid air can condense on the diffuser and drip on the occupant.
Avoid blowing cold air directly onto exterior glass, which can cause condensation.
Design diffusers with throw and velocity in mind to avoid drafts and ensure occupant comfort.
Insulation
The location of insulation on the ductwork and piping systems shall be thoughtfully considered to avoid condensation and mold growth while balancing acoustic needs. The following should be considered in the equipment specifications:
Insulate any system (air or water) that operates below the space dew point temperature.
For ductwork:
Use external wrap for outside air ducts. Duct liner on outside air ductwork can absorb moisture and produce mold and mildew.
Avoid internal liner insulation unless needed for sound attenuation. If needed, limit it to the first 15 feet downstream of the noise-producing equipment.
If ductwork is exposed and aesthetics are key, consider using double-wall ductwork. Double-wall ductwork is more costly and should be considered in the project budget.
For piping:
Insulate all chilled water, condenser, domestic cold-water, and condensate lines.
Ensure there are no thermal breaks at supports or fittings.
Designing HVAC systems in humid climates requires more than just standard cooling calculations. From equipment sizing to insulation and material selection, every detail matters when moisture is in play.
By following these best practices, you can ensure your systems perform reliably, maintain occupant comfort, and withstand the challenges of high humidity.
Dealing with a high-humidity challenge? We would love to help. Contact us to start the conversation by clicking below or e-mail Stacey Richardson at srichardson@360eng.com.
As summer comes into full swing and temperatures begin to climb, commercial and industrial facilities face increasing pressure to ensure their HVAC systems are operating at peak performance. One of the most critical components in large-scale cooling systems is the chiller. Whether you’re managing a hospital, data center, office complex, or manufacturing plant, upgrading your chiller system before the summer heat hits can make a significant difference in energy efficiency, occupant comfort, and operational reliability.
Here’s what you need to know before investing in a chiller system upgrade.
1. Assess Current System Performance
Before considering an upgrade, conduct a thorough performance assessment of your existing chiller system. Look for signs of inefficiency such as:
Rising energy bills
Inconsistent cooling
Frequent maintenance issues
Equipment nearing or past its expected service life
Modern chillers are significantly more efficient than those installed even a decade ago. If your system is more than 15 years old, an upgrade could reduce energy consumption significantly.
2. Understand Your Cooling Load Requirements
Chiller systems should be sized based on actual cooling load demands, not outdated or estimated figures. Consider the actual occupancy and usage of your building, as well as any other facility upgrades that may have been implemented previously (such as window replacement, improved insulation, even office equipment moderniziations). Over- or under-sizing can lead to inefficiencies, increased wear and tear, and higher operational costs. A professional load analysis will help determine the optimal capacity and configuration for your facility’s current and future needs.
3. Explore Energy-Efficient Technologies
Today’s chiller systems come equipped with advanced technologies that offer superior performance and energy savings:
Variable Speed Drives (VSDs): Adjust compressor speed based on load, reducing energy use during partial load conditions.
Magnetic Bearing Compressors: Eliminate oil and reduce mechanical friction, improving efficiency and reliability. These systems typically allow for significantly greater turndown at part-load conditions as well—that is, the chiller can operate efficiently at reduced capacity, conditions at which other types of chillers would need to shut down entirely to protect their internal refrigeration components!
Free Cooling Options: Use ambient air or water when conditions allow, bypassing the compressors (i.e. the primary energy users in the cooling system) entirely to save energy.
Incorporating these technologies can also help your facility qualify for utility rebates and sustainability certifications like LEED O+M.
4. Consider System Integration and Controls
Upgrading your chiller is only part of the equation. Integrating it with a modern Building Automation System (BAS) allows for real-time monitoring, predictive maintenance, and optimized performance. Smart controls can adjust chiller operation based on occupancy, weather forecasts, and energy pricing, further enhancing efficiency.
5. Plan for Downtime and Installation
Chiller upgrades can be complex and may require temporary system shutdowns. Planning ahead is crucial to minimize disruption. 360 can help building owners navigate these challenges, working with vendors, contractors, and facility staff to:
Schedule installation during off-peak hours or cooler months
Coordinate with other building systems
Ensure proper commissioning and testing
A well-executed upgrade plan ensures a smooth transition and long-term performance benefits.
6. Evaluate Lifecycle Costs, Not Just Initial Price
While upfront costs are important, the total cost of ownership—including energy use, maintenance, and lifespan—should guide your decision. A slightly more expensive chiller with higher efficiency and lower maintenance needs can pay for itself in just a few years.
7. Partner with the Right Engineering Firm
Choosing the right HVAC design engineering partner is key to a successful chiller upgrade. 360 Engineering is a firm with:
Proven experience in chiller system design and retrofits
Knowledge of local codes and energy standards
A track record of delivering energy-efficient, cost-effective solutions
Final Thoughts
Upgrading your chiller system before the summer heat arrives isn’t just a smart move—it’s a strategic investment in your facility’s performance, sustainability, and bottom line. With the right planning and expertise, you can ensure your building stays cool, efficient, and resilient all season long.
Need help evaluating your chiller system? Contact our team of HVAC design experts today to schedule a consultation.
In today’s world of high-performance buildings and sustainable design, one technology is quietly transforming how we think about indoor air quality and energy efficiency: the Energy Recovery Ventilator (ERV).
At its core, an ERV is a smart system that captures the energy from outgoing stale air and uses it to condition incoming fresh air. This process not only reduces the load on heating and cooling systems but also ensures a consistent flow of clean, filtered air throughout the building, critical for both comfort and occupant health.
Image Credit: greensavers.com
So why are more engineers, architects, and building owners turning to ERVs?
Energy Efficiency: ERVs can recover up to 70–80% of the energy from exhaust air, leading to significant reductions in HVAC energy use.
Indoor Air Quality: In a time where indoor air quality is under the microscope, ERVs provide a continuous supply of fresh, filtered air—without the penalty of higher energy bills.
Code Compliance: As building codes and green certifications push for better ventilation and lower energy footprints, ERVs are becoming a go-to solution to meet both requirements simultaneously.
Image Credit: 2050-materials.com
Whether it’s a high-rise office, school, hospital, or even a multi-family residence, integrating an ERV into the mechanical design can make a measurable difference in performance and sustainability.
At 360 Engineering, we specialize in designing HVAC systems that work smarter—and ERVs are one of the most effective tools in our playbook.
Want to learn more about how ERVs can improve your building project? Reach out or follow us for more insights into engineering innovation that breathes life into buildings.
The National Renewable Energy Laboratory (NREL) is a leading research facility on clean energy and alternative fuel sources. This year, the Flatirons Campus and Wind Facility are completing their first ground-up building construction in several years, led by the HDR team. The new state-of-the-art building will act as the central control facility for all research efforts on the Flatirons Campus.
Modernized building construction requires a modernized mechanical and plumbing system to complement the building design. During the early phases of design, five (5) different mechanical systems were considered, with a wide range of factors including ease of maintenance, energy efficiency, and utilization of heating and cooling utilities. Ultimately, after energy modeling, lead time considerations, and cost considerations, NREL opted to proceed with the first Variable Refrigerant Flow (VRF) mechanical system on their Flatirons Campus.
The VRF system includes a packaged heat pump Dedicated Outdoor Air Unit (DOAS) with a heat recovery wheel for low-energy preconditioning of the building. The DOAS provides ventilation air to each indoor fan coil unit, easily complying with code requirements for the varied room types within the building. The building hosts conference spaces, electronics labs, a data center, and general office space.
The control facility was optimized to maximize floor space, presenting the unique challenges of configuring mechanical and plumbing systems in the limited plenum space. The team utilized REVIT during design to model systems beyond the 2D of CAD and capture any constructability conflicts early on.
The building is nearing the end of construction and the final stages of mechanical commissioning, with an occupancy slated for April. The unique mechanical and plumbing integration of exposed versus concealed aspects balances with the architectural aesthetics to create a truly beautiful building that is both pretty to look at and functions as a high-tech research facility. It’s great when these two design objectives find a way to cooperate!
When it comes to commercial water heaters, building owners and tenants have several options to choose from, each with its own set of advantages and disadvantages. As plumbing engineers, we know that understanding these options is crucial for recommending the best solutions to our clients. In this blog post, we’ll explore the different types of commercial water heaters, including electric resistance, heat pump, gas-fired, and the differences between tankless and storage tank types. We’ll also touch on the Denver Energy Code changes and restrictions related to service water heating. Our goal is to help everyone “feel the heat” this Valentine’s Day!
Electric Resistance Water Heaters
Electric resistance water heaters are commonly used in many settings, especially for tenant spaces with relatively small fixture hot water loads or in areas without natural gas or propane readily available. They work by using electric resistance heating elements to conduct heat to the water stored in a tank. These heaters are relatively simple to install and maintain, making them a popular choice for many owners.
Pros:
Easy to install and maintain
Widely available
Can be installed in various locations (no venting to the exterior required)
Cons:
Slower recovery rate compared to gas-fired water heaters
Higher operating costs compared to gas-fired or heat pump water heaters
Heat Pump Water Heaters
Heat pump water heaters are an energy-efficient alternative to traditional electric resistance heaters. They work by transferring heat from the surrounding air to the water, using a refrigeration cycle. This process makes them significantly more efficient, as they use less electricity to heat the same amount of water—it’s generally more efficient to move energy from one medium to another rather than “create” it by burning gas or heating up resistor.
Pros:
Highly energy-efficient
Lower operating costs
Environmentally friendly
Cons:
Performance can be affected by ambient temperature
Higher upfront cost
Requires a well-ventilated space, or potentially outdoor space for the condenser
For split systems with outdoor condensers, requires water piping to run outside—which creates additional design requirements for freeze protection
Gas-Fired Water Heaters
Gas-fired water heaters use natural gas or propane to heat the water. They are known for their fast recovery rates and lower operating costs compared to electric resistance heaters (until electricity and gas prices start to coincide). These heaters are a popular choice in areas where natural gas is readily available.
Pros:
Lower operating costs
Faster recovery rate
Reliable performance
Cons:
Potential for gas leaks
Requires a gas line and proper ventilation (both combustion air intake and flue exhaust to the outside)
Higher installation costs
Tankless vs. Storage Tank Water Heaters
Another significant decision to face is choosing between tankless and storage tank water heaters. Each type has its own set of benefits and drawbacks.
Storage Tank Water Heaters
These are the traditional water heaters with a large tank that stores hot water until it’s needed. They are available in various sizes, typically ranging from 10 to 120 gallons (though both larger and smaller options exist as well).
Pros:
Lower upfront cost
Simple and reliable
Can provide hot water to a large quantity of fixtures simultaneously
Cons:
Higher energy consumption due to standby heat loss
Takes up more space
Limited hot water supply, depending on the provided recovery rate (higher recovery rate equals higher energy usage)
Tankless Water Heaters
Tankless water heaters, also known as on-demand or “instantaneous” water heaters, heat water only when it’s needed. They do not store hot water, which eliminates standby heat loss.
Pros:
Energy-efficient
Endless hot water supply
Compact size
Cons:
Limited flow rate (the higher than required instantaneous hot water flow, the greater the energy required)
Higher upfront cost
May require upgrades to electrical or gas systems
Denver Energy Code Restrictions
The Denver Energy Code has specific restrictions on the types of water heaters that can be installed in new and existing commercial buildings. As of March 1, 2023, the code requires partial electrification for all existing commercial and multifamily buildings when replacing gas-fired space and water heating equipment1. This means that gas-fired water heaters are being phased out in favor of more energy-efficient options like electric heat pump water heaters2.
For commercial buildings, the Denver Energy Code also encourages the use of electric heat pump water heaters and restricts the installation of new gas-fired water heaters3. These changes are part of Denver’s broader efforts to reduce carbon emissions and promote sustainable building practices.
Valentine’s Day Jokes
And because you asked for it, here are some Valentine-themed jokes to help everyone feel the heat (or maybe just make us plumbing engineers chuckle):
What did the tankless water heater say to its Valentine? “With you, I never run out of love!”
Why did the electric water heater break up with its partner? It just couldn’t handle the constant resistance!
What did the water heater say to its crush on Valentine’s Day? “You make me feel like my T&P valve is about to go off!”
Conclusion
Choosing the right water heater for a commercial building involves considering various factors, including energy efficiency, operating costs, and installation requirements. Electric resistance, heat pump, gas-fired, storage, and tankless water heaters each have their own advantages and disadvantages. Understanding these options and the local energy code restrictions can help businesses make informed decisions.
Whether you’re a business owner, plumber, or engineer, understanding the intricacies of water heaters is key to ensuring a comfortable working environment—just like keeping the warmth alive in your Valentine’s heart!
The new year has come and passed and 2025 is in full swing! This also means the next stage of the HFC refrigerant phase-out is here, so let’s review what that means for us architects, engineers, and contractors.
As a reminder, from our 2023 blog here, the AIM act was passed in 2020. The American Innovation and Manufacturing (AIM) Act gives the Environmental Protection Agency (EPA) the authority to regulate and phase down the production and use of hydrofluorocarbon (HFC) refrigerants. HFCs are known greenhouse gases, most of which are rated with a global warming potential (GWP) several thousand times that of carbon dioxide (which is the baseline of the scale, with a GWP of 1). The EPA has thus banned HFCs by setting limits to the allowable GWP of refrigerants manufactured or imported for use in the U.S. To Implement this ban, the EPA has implemented phase-out dates for the manufacturing and installation of different types of HVAC equipment, see below:
1/1/2025: The manufacturing and import stop date for direct expansion (DX) and heat pump systems such as rooftop units, water source heat pumps, and split systems (including mini-split and multi-split heat pump systems)
This equipment has 1 year to be sold and installed until (1/1/2026).
1/1/2026: The manufacturing and import stop date for Variable Refrigerant Flow (VRF) systems.
This equipment has 1 year to be sold and installed (until 1/1/2027)
If the construction project was issued an approved building permit prior to 10/5/2023, then installation is allowed until 1/1/2028.
This means that the DX and Heat Pump equipment that we select and specify on our projects (other than VRF) can no longer be manufactured or imported with R-410A refrigerant. Going forward we must design and specify DX and Heat Pump equipment with refrigerants that meet the GWP limitations set by the EPA, which will mostly be R-454B and R-32 in our industry.
The biggest impact of these new refrigerants is the change in refrigerant classification. R-410 is classified as an A1 refrigerant that has low toxicity and no flame propagation (the lowest flammability). The newly used R-454B and R-32 refrigerants are classified as A2L refrigerants. A2L refrigerants have a low toxicity, with low flammability. This increased refrigerant classification from an A1 to an A2L refrigerant has increased code requirements to ensure the safety of the occupants, which must be considered in our designs going forward.
With the transition to these new A2L refrigerants in full swing, the following should be considered for projects in varying stages of the design and construction process:
Projects in design should only be specifying equipment with low GWP refrigerants (other than VRF equipment). Code calculations shall be completed throughout design to implement any requirements needed to meet all code requirements. This could require transfer openings between rooms, refrigerant detection systems, or refrigerant exhaust systems.
If projects that had been put on hold or had a long break between phases are coming back to life, the current mechanical system design shall be discussed with the mechanical engineer to confirm the implication of the new refrigerants on the project and what changes may be required. This may require some redesign of the mechanical systems, which could include changing the mechanical system type, reselecting DX equipment, completing refrigerant calculations, and implementing design changes to meet the requirements of the code. The time to make these changes should be considered between the engineer, the architect, and the owner.
Projects in the beginning stages of construction shall be coordinated with the contractor to confirm if the DX equipment has been ordered or can still be ordered, received, and installed by the EPA-required dates. If the specified equipment with the old refrigerant cannot be ordered and/or installed, the engineer will need to complete the code-required refrigerant calculations to ensure the new refrigerants work with the design or implement design changes to meet the code.
With the shift to the newest refrigerants, one of our biggest restrictions as the selecting and specifying engineers over the past several months has been the ability to actually select the equipment with the new refrigerants and attain the refrigerant charges, equipment capacities, and efficiency ratings. Over the last month, a majority of manufacturers have confirmed the availability to select equipment with the new refrigerants, which allows us to finalize equipment selections and calculations. While there are still some minor restrictions in the availability of equipment specifics as the manufacturers continue to get the new equipment tested, the major equipment information is mostly available to move forward with selections.
In summary, the new refrigerant changes are upon us and will require additional calculations and coordination for DX systems that should be considered for projects in various stages of design and construction. The equipment manufacturers have made big strides to provide us, as the engineers, the information we need to get equipment selections, but there may be some minor lagging information we may need to wait for confirmation on. Overall, 360 Engineering is excited to move away from the limbo between two refrigerant types and start moving toward a more sustainable future.
While we love sharing our projects and technical knowledge throughout the year, we thought mixing it up this month and sharing some of our staff’s favorite holiday treats would be fun. We hope you enjoy these recipes and stories as much as we do. Maybe you’ll even have an opportunity to make some of these tasty treats over the holidays. If so, let us know; we’d love to hear about it!
The National Park Service was looking to renovate its existing Lodge building and cabins at the Ozark National Scenic Riverway Big Spring site in Missouri. The site includes thirteen (13) rentable cabin buildings, a concessioner’s house, a laundry building, a museum building, and the riverfront lodge. The area had experienced historical flooding in 2015 where the lodge itself was in 10’ of water on the main level photographed above. This flooding closed the park site, and all the buildings sat dormant until this project was initiated. The lodge experienced the worst damage, and all systems required full replacement. The other buildings onsite were lucky to be higher on the hillside and were not flooded. The lodge building provides spaces for park users and guests to congregate and eat meals and serves as a launch point on the river, where there is newly built dock access. This lodge is also outfitted with a commercial kitchen for the concessioner to provide meals for the guests.
Close Coordination & Minimizing Mechanical Space Needs
Missouri experiences high humidity, so the mechanical systems were designed with full dehumidification in mind. The existing systems serving the lodge were non-existent; there was no heating or cooling serving the building previously. This required new mechanical space to be created outside to account for these cooling and heating needs. These new outdoor systems serving the lodge are two heat pump condensing units and a makeup air unit for the kitchen.
Makeup Air Unit at the Kitchen
The makeup air unit was a tight fit, but we were able to work with the existing area on the side of the lodge. The two new heat pump condensing units, however, were going to require a new mechanical yard to be formed. This lodge is a historical structure, so everything needs to be done to maintain the current aesthetics. We took extensive care to minimize the mechanical yard footprint and position it to hide mechanical equipment from the general public’s view.
Mechanical Yard Behind the Lodge
Ultimately, the mechanical space created was the ideal size and location to leave the least impact on the site while still providing complete heating, cooling, and dehumidification to what was formerly a hot, cold, and stuffy building.
Air Handling Units Above the Ceiling
We had new heat pump air handling units installed above the ceiling inside the building. These units were about as large as you could fit within these existing ceiling cavities, but through close coordination with our structural engineer and architect, we developed solutions to make these units semi-removable for ease of replacement at the end of their life and provide ideal access for ease of serviceability during their operational lifespan.
Equipment Sizing
Air Distribution
Insulation
