Noise! Noise! Noise! Reduce The Noise!

The Holidays are upon us, with all the excitement and the parties. As the Grinch says, “And Then! Oh, the noise! Noise! Noise! Noise! There’s one thing I hate! All the NOISE! NOISE! NOISE! NOISE!”

Now, I am no Grinch about the holidays, but prior to my tenure here at Melink I worked for nearly 10 years as an Environmental Health and Safety Manager within a large chemical facility, and there were various work areas which exceeded noise thresholds requiring hearing protection. It was LOUD. This is where I became cognoscente of NIOSH (National Institute for Occupational Safety and Health) standards for hearing conservation,

NIOSH states continued exposure to noise above 85 dBA (adjusted decibels) over time will cause hearing loss. The volume (dBA) and the length of exposure to the sound will tell you how harmful the noise is. In general, the louder the noise, the less time required before hearing loss will occur. According to the NIOSH, the maximum exposure time at 85 dBA is eight hours.

Although we may not be able to control the noise of the holiday party or the loud toys the children will receive on Christmas day, perhaps within the working environments of commercial kitchens we can make drastic improvements and reduce the overall noise level.

Studies have been conducted over the years and dependent on many variables such as the size of the kitchen spaces, the duration of peak activity, and other various factors the overall noise level at times approach or exceed the 85dBA level, sources show a typical restaurant operates at 80 dB, although this value does not trigger hearing protection, some restaurants are known to reach 110 dB at times which is the noise level of a jackhammer! Think of the last time you were at your favorite restaurant and seated near the kitchen entrance versus the opposite side of the room.

Demand control kitchen ventilation can help not just provide energy savings but also reduce the noise levels drastically, especially over an 8-hour timeframe for employees in the kitchen spaces. When researching kitchen exhaust fans one will find that the noise levels are reported as a “sone” which depending on the static pressure of the design the noise levels can vary. A sone is a unit of loudness, how loud a sound is perceived. Doubling the perceived loudness doubles the sone value. Within fan specs of kitchen exhaust fans manufacturers indicate the “Sones” level for example a 5hp kitchen exhaust fan has a sone level ranging from 16.5 to 26 sones dependent on duct design. Per the decibel level and sones conversion chart this is equivalent to around 68.3 to 74.9 dB!

Now considering utilizing a temperature and optic based demand control kitchen ventilation, such as Intelli-Hood, can reduce fan speeds by 30-45% average fan speed over a 24hr period consider the reduction of noise exposure this provides. It is not uncommon for customers post installation of a Melink Intelli-Hood system to recognize significant noise reduction, many times commenting that during food prep hours, although the fans are “turned on” they operate at a minimum speed and it sounds like they are not even operating!

Perhaps you are in a position of influence of the decision to retrofit Demand Control Kitchen Ventilation, or perhaps evaluating and analyzing the opportunity for a client. Remember that there is more savings than simply energy that can be considered when evaluating demand control kitchen ventilation.

Effects of dynamic air flow in kitchen environments and the importance of air balancing


As we all know, the hospitality industry is developing a lot these days. Owners are investing heavily into their hotels in order to globalize them and create unique destinations. This development is mainly due to the increase in international tourism and business travel driving the need to create different cuisine options. The multitude of cuisine options and equipment designs can have a significant impact on dynamic air flows and energy consumption.


In the hospitality industry, the focus is being given to the improvement of centralized kitchen air conditioning to ensure that the chefs working in the midst of heat are safe and comfortable. Even small-scale kitchens are focused on providing air conditioned kitchens now more than ever.


In the earlier days, importance was generally given to extract and discharge of exhaust air alone. Whereas now, in trending commercial kitchen ventilation system, the following ventilation systems are present to do air balancing and bring comfort in the kitchen zone-wise:

  • HOT Kitchen Zone – When cooking appliances are present, exhaust air and fresh air (makeup air) systems will be present to extract thermal plumes and radiant heat.
  • COLD Kitchen Zone – The preparation area and refrigeration area have conditioned air and return air systems present.
  • Dish Washing Zone – With the heavy output of steam, systems are in place to extract the steam immediately and recycle makeup air through the area.

Dynamic Air flow occurs due to the following reasons:

  • The heat load is not calculated per the equipment specifications.
  • Selection of improper kitchen equipment that leads to variation in heat load. Examples include wrong burner design, equipment without proper insulation, wrong electrical appliance selections.
  • High air draft transfer through doors/service door/high velocity diffusers
  • Equipment placement changes. An example would be changing the positions of equipment against the original kitchen design.
  • Extraction hood is undersized as it affects suction.
  • Increase in the number of people in the building.
  • Improper selection of exhaust fan, make up air fan, and exhaust & make up air ducting system

As a result of the air draft energy savings plummet!


Something that I have observed quite often, is the high draft air transfer through different doors. This is a primary cause of dynamic air flow. Optimal kitchen design would allow the natural hot air from cooking to go undisturbed.

Service door opening affecting dynamic air flow.Service door opening allowing natural air flow.

In the 1st image above, the service door is open so the hot air that is rising is disturbed due to the high draft air from the next room, creating turbulence. The high draft should be balanced to decrease energy loss.

In the 2nd image above, the service door is closed allowing the hot air to rise without disturbance.

When there is a turbulence, the temperature in the kitchen will quickly rise as the extraction does not happen correctly and it combines with exhaust and supply air. Therefore, this makes the kitchen staff become very uncomfortable, air conditioning is increased to cool down the kitchen, and the exhaust is ramped up. Because of this, extra energy is used when it could have been avoided. If this is constantly being repeated, it will result in discomfort, hygiene will be affected, and there will be a huge loss of energy.

As you are designing your next kitchen, be cognizant of the fact that kitchen design impacts more than meets the eye. Kitchen efficiency goes beyond the layout that makes it easiest for your staff to work in, it entails energy usage and safety as well.

Energy Upgrades In Prison Facilities

It is no secret that many prison facilities are outdated, understaffed, and overcrowded. Sadly, these problems can all be traced back to being underfunded.  With large pressing problems like this, it makes the idea of certain energy upgrades in prisons like installing a new LED light fixture or flow meters on hydronic components seem miniscule while the impact could greatly help the underlying problems.

The Problem – “There’s only three ways to spend the taxpayer’s hard-earned when it comes to prisons.More walls. More bars. More guards.” – Shawshank Redemption

Although it may seem like this statement is true, most of the costs associated with state run facilities is lumped into personnel costs within the operating expenses. Salaries, overtime, and benefits comprised over 66% of the cost to run state facilities. Additionally, an average of 17% of funding across the nation went to facility maintenance, prison programs, debt services, and legal judgments. This data tells us that most of the cost of prisons goes unsurprisingly, to operating costs. The operating costs can range from your day to day maintenance, to the utility bills, to providing food and supervision for inmates. The average salary of correctional officers in the US is $37,717 per year, so adding even one more CO to help an understaffed facility can have a substantial effect on the budget.

The Solution – Lower Operating Costs

However, the problem with initiatives and projects to reduce operating costs, is that they are met with red tape. Every state has their own nuances but all capital expenditures go through lengthy processes to determine what is necessary and when. So, how can a facility take control of own their operating costs without the capital expenditures? For multiple energy efficiency and water conservation measures in one project, energy service performance contracts can be a powerful tool if managed properly. These projects can range from low flow facets, to LED lighting, to control systems, to mechanical system replacements.

However, some states have different laws regarding performance contracts so if this route is not an option, individual conservation measures can be implemented creatively. For example, demand control kitchen ventilation is a relatively low-cost measure with a high ROI, making it a versatile measure for performance contracts and as a standalone facility upgrade. By slowing the kitchen exhaust fans in relation to the cooking activity, savings are realized through fan energy reduction and reduction of conditioned air that is wasted. In many cases there are even lease options among other financing routes that could make your project cash flow positive from the first month of implementation! With the saved money that would be going toward the electric bill, the extra cash can be used for other costs across the facility.

Putting Your Savings to Work

Implementing energy efficiency products like DCKV can save you money, but how much are we talking? For a large facility, let’s say you save $30,000 a year on your electric and conditioned air. In North Carolina, that is enough to cover the cost of one inmate for 335 days or 335 inmates for one day. In Florida, that is enough to cover the costs to house and supervise one inmate for 561 days or the salary of an entry level Correctional Officer. Why is Florida’s cost per inmate so much less than North Carolina? The state completes a lot of ESCO projects, so overall, their facilities are more efficient.

In the end implementing energy efficient technologies and practices, not only helps your prison run more efficiently, it reduces operating expenses so your cash can be used where it makes a  bigger impact; paying for more CO’s, building upgrades, and additional programs to reduce the recidivism rate.