Prevent Sick Buildings: Why Positive Building Pressure Matters

Can a building get sick? I’ll give you the answer up front: Yes, sure, most definitely — a building can get “sick.” You may ponder… “But how can a building become sick? It is an inanimate object. It doesn’t live and breathe like humans!” On the contrary, your building is a living object. The main factor making your building come alive is its people: your customers, employees, and outside partners (think mail delivery or an overnight cleaning crew). Let’s dive into what factors can make a building sick and why maintaining positive building pressure is so important in prevention.

What Makes a Building Come Alive?

First, consider what may make your building come alive (or ultimately “infect” it):

  • Supplies
    The products you bring in (from any point of origin) may have outside contaminants or be perishable. As you know, perishables may emanate odors or fumes.
  • Chemicals
    You must account for chemicals or cleaning supplies in their controlled rooms (where exhaust is extremely important). 
  • Restrooms
    Consider the restroom facilities. Restrooms, especially those open to the general public (i.e. in a lobby area) can encounter high volumes of traffic and behaviors that may not meet sanitary standards. 
  • HVAC System(s)
    Your HVAC system is a key element bringing your building to life. With proper cleaning and maintenance, they are designed to provide comfort on demand. Heating and cooling are crucial amenities that have grown to be a must-have and are mandated by federal and local guidelines. 

When you take all these factors into account, it’s easier to understand how a building can become “sick.”

Sick Building Syndrome symptoms

Facility Managers: How to Prevent Sick Buildings

So how can a facility manager or building owner help to prevent sickness in a facility? As a professional in the HVAC industry, my primary goal is to earn your trust to maintain the wellness of your building’s HVAC system. Think about it — you can’t control others’ actions. There is no way to determine someone’s state of health as they are in your establishment. But you can control the HVAC system and make sure it is properly maintained to be a healthy system!

A little-known fact about HVAC systems that I will stress the importance: FRESH OUTSIDE AIR IS NEEDED TO MAINTAIN A POSITIVE BUILDING PRESSURE AT ALL TIMES. What does this mean, and why is it important?

  1.  Your restaurant, retail store or office building, has many moving parts to bring it alive, has to breathe. Like any living thing, it requires oxygen to replace the carbon dioxide. The equation should result in bringing in a greater amount of fresh air than the carbon dioxide, chemicals, fumes/odors, and cooking effluents that the building creates. When this happens, there should be a slight positive pressure from the inside of your establishment that pushes outward at your doors and drive-thru windows.  A proper HVAC test and balance (TAB) by an NEBB-Certified firm like Melink can help you achieve this goal.  

  2. A common oversight that people make is assuming, “My building is positive. We’re in good shape.” But how sure are they that the lungs of the HVAC system are clean and free of operational damages? Many times, I have encountered damaged and clogged filtration components within an HVAC system that may lead to costly repairs to your equipment and structural damages:
  • Clogged or missing outside air intake filters
  • Clogged, missing or inadequate air filters
  • Clogged evaporator and condenser coils
  • Clogged and inadequate fan blower wheels
  • Mold and mildew
  • Trapped small animals that lead to contaminations
  • Contaminated duct work that eventually shows up on the supply, return and exhaust grilles throughout the establishment 
Checking HVAC ductwork for positive building pressure

All these issues work together to create a sick building.  The opposite of positive pressure is that dreaded negative pressure. Every time your facility’s doors open, all of the outside air conditions are sucked into the building.  These elements can be hot or cold air, humidity, airborne pathogens, and odors. The humidity attaches to the chilled supply diffusers and grilles, creating moisture buildup that drips onto your floors, tables, customers, and clients.

Checking HVAC filters for positive building pressure

Of course, it’s not feasible for a facility manager to know the ins and outs of every HVAC system of every facility he/she manages. So let us do the work for you! Melink Corporation’s T&B technicians can be your eyes and ears to help your facilities maintain positive building pressure. We are an army of application engineers with skilled LEED and NEBB certifications. Our company is nationwide and has more than 30 years of experience. Along with services that will help you on your way to a healthy building, we offer a monitoring system and demand ventilation systems that will alert you when problems or concerns arise.  These services, along with reliable routine maintenance will minimize uninterrupted service to your most important people. We can help you protect your customers, employees, and outside partners from sick buildings.

Coronavirus & Indoor Air Quality

Now, maybe more than ever, many businesses are concerned about indoor air quality (IAQ) to protect employees and customers from coronavirus. With the current spread of COVID-19 across the globe, it is important that we are all taking the necessary steps to reduce the spread of the virus. As part of this, it is important to recognize how your HVAC system can impact your IAQ during long hours of social distancing, as well as steps that can be taken to limit the spread of the virus in buildings.

In a normal year, the typical American spends 90% of his or her time indoors. With current guidelines about social distancing, this number is expected to increase over the next few months. Prior to recent events, the American Medical Association stated they believe 50% of illnesses are caused, or aggravated, by polluted indoor air. Furthermore, per the EPA, indoor air contains two to five times more pollutants than typical outside air.

Coronavirus
Source: Centers for Disease Control and Prevention

So what does this mean for the COVID-19 crisis? Now that we have learned the novel coronavirus can be spread via airborne transmission when in close contact, there is the possibility that the HVAC system could cross-contaminate. That means air from an infected person could recirculate through a facility’s HVAC system and infect another individual. An example of this is how cruise ships experienced severe outbreaks. All cabins share an HVAC system, which is working as a mode of transmission from one individual to another.

While this risk of shared indoor air cannot be completely eliminated, there are a few items that can be addressed to reduce the potential for transmission through the HVAC system including:

  • Enhanced Ventilation & Ventilation Effectiveness
  • Source Separation
  • Air Filtration
  • Operable Windows

First and foremost, facilities should ensure their HVAC equipment is bringing in the correct amount of outside air required by the engineered designed plans, as well as managing the pollution and exhaust from your building properly. To further mitigate this risk, one should attempt to increase the percentage of outside air being brought into a facility to a higher percentage than minimally specified. In doing this, the equipment will reduce the amount of air being recirculated through a building. This will not only reduce “shared air,” but will also decrease levels of CO2 and other indoor air pollutants that can create an uncomfortable, or unhealthy, facility.

For a residential facility, where air source isn’t as easily controlled, it can also be helpful to open windows to bring in fresh air to any given room. In addition, it is worth verifying that any fresh air being brought in is being evenly distributed. If it isn’t, certain rooms may have less air turnover, meaning that the air isn’t circulating in and out of the facility properly.

The next few months may be difficult with longer hours than normal spent indoors. It is important that we are all taking steps to minimize the spread of coronavirus and other airborne illnesses both now and in the future. Melink offers products and services specifically designed to track, trend, and improve indoor air quality. Click to learn more about our HVAC test and balance services or PositiV® building health monitor, or contact us today. Our techs are the certified pros in indoor air quality — let us help you mitigate your risk while protecting employee and customer wellness.

How Indoor Air Quality Influences Wellness

Indoor air quality (IAQ) can influence the cold/flu season. According to the American Medical Association, 50% of illnesses are caused or aggravated by polluted indoor air. The U.S. Environmental Protection Agency (EPA) believes this is because indoor air contains two to five times more pollutants compared to typical outside air.

While the average person spends 90% of their time indoors, many groups of people considered to be “high risk” spend even more time indoors. These populations include but are not limited to babies, the elderly, and those with health conditions. So when you consider the ample amount of time people are spending indoors with potentially polluted air, it is easy to understand how IAQ can be linked to sickness. In fact, IAQ poses such a large risk to human health globally that the EPA recognizes it as one of its top 5 health hazards.

Sick building showing indoor air quality

While most people think that poor IAQ is easily noticeable because they can sense it through vision or smell, this is not normally the case. Many times, the IAQ in a facility may be poor because the CO2 level is far higher than recommended. Typically, a “safe” level of CO2 is between 400-1,000ppm, but levels can reach as high as 2,000ppm. At this high level, occupants can experience headaches, sleepiness, decreased cognitive function, and increased heart rates.

To ensure that CO2 levels are kept in check, it is best to have a building health monitor (such as PositiV) installed to examine these levels. If the CO2 level is above the 1,000ppm mark, it is best to examine the outside air intake on the air conditioning equipment to ensure the facility is receiving the proper air changes per hour and enough fresh air is entering the facility.

TOP 3 Points to Consider Before Scheduling an HVAC Balance

There are a few important items that you want to take into account before you schedule an HVAC balance. While these 3 points may seem obvious, there are many instances where a technician gets onsite and the job-site isn’t ready or they can’t access areas that they need. These tips can save time and money for everyone!

1. HVAC equipment is installed and operational.

This one seems like a no-brainer! However, there are always occurrences when a technician arrives onsite to perform a balance and necessary equipment either hasn’t been installed or isn’t properly operational. Examples include VAV’s or dampers that haven’t been installed, or a RTU that isn’t operational.

Ensuring that all ductwork has been completed, balancing dampers are properly installed, any grilles, registers and diffusers are installed, and the RTUs have clean filters helps make sure a technician can provide a proper air balance, as well as mitigate any potential return service costs. Making sure that all equipment (especially RTUs) has undergone a proper start-up to confirm power should always be completed ahead of Melink’s arrival.

2. All HVAC equipment can be easily accessed by a technician.

Another hindrance to any proper test & balance is not being able to access the necessary equipment. This includes equipment installed inside the building, as well as equipment on the roof. When working with a customer located inside a mall or shopping center, security and approved roof access becomes another added component.

Melink typically requires assured access to all applicable HVAC system equipment, including RTUs, VAVs, Exhaust Fans, dampers, etc. Access to fully open dampers, ceiling-height diffusers, and thermostats that may be in an office is necessary to properly complete the balance. Our Account Coordinators will also discuss roof access, security measures, and accessibility to ladders or lifts.

3. Allotting adequate time (2-3 weeks) to schedule and complete the balance.

Though some seasons are busier (or slower) than others, our goal at Melink is to provide every customer the same level of service excellence no matter the time of year. This includes communication with the customer, scheduling the site visit with one of our National Network technicians, performing the balance and working with the customer on any punch-list items, and finally, providing a certified test & balance report.

Our team of National Account representatives and technicians work with the customer through each step of the process. Scheduling an HVAC balance with Melink approximately 2-3 weeks out from turnover will help to ensure a proper and complete balance. It also allows enough time to work through any punch-list items or lingering comfort issues for the customer.

National and Independent Test and Balance: We Go Where You Are!

National retailers, restaurant chains and commercial property groups all have similar HVAC needs all across the country.  When going to a Starbucks and asking for a “Grande Pike”, we have a set expectation of what we will experience when the barista delivers that 16 oz cup of perfection, right?  Why should commercial buildings be any different?  Don’t the brand managers and facilities teams want their building occupants to have the same, consistent comfortable, healthy experience when inside of their buildings?  Don’t they want their customers and employees to enjoy a safe, comfortable, energy efficient indoor environment at every location nation-wide?  We find the answer to be a resounding YES!

In 1987, founder Steve Melink saw the need for consistent, national, test, balance and commissioning services for national restaurant and retail chains.  While test and balance companies weren’t new, there was no one fulfilling the services in an unwavering manner across the entire nation. Companies either performed work in a small region, or they hired out whomever they could find across the country as jobs popped up. This not only left varying and unreliable reports, but also no standard across the nation for larger national accounts. What was done at one location, may have been measured differently at another, or not even checked at all! Steve understood the need for one company to be able to deliver reliable and consistent services and reports to all business, regardless of location.

13,000+ projects completed since 2014!!

Fast forward 32 years.  Today Melink Corporation is still known as the standard for national test, balance and commissioning services and serves many of the world’s largest and fastest growing restaurant and retail chains.  In the same vein as the Starbucks example, our customers expect consistency and quality no matter where they are building and remodeling.  We don’t leave our quality to chance or to the general contractor’s sub, we hire and train the best technicians and engineers.

With our 100% self-performing, independent, national team of Test, Balance and Commissioning professionals, Melink takes our quality on the road, each and every day.  Simply put “We Go Where You Are”!

Are you struggling to find someone that can service any of your locations? Contact our team by phone at 877-477-4190 (toll-free) or online at [email protected] or here…we look forward to helping find a solution for your business!

The Melink Umbrella

Are you an existing customer or follower of Melink?  I’m guessing the answer is “yes” if you’re reading this, so what all falls under the “Melink Umbrella”? In the Cincinnati, OH region, we’re best known for our super-green energy efficient HQ building. Those things help to show who we are as a company; however it isn’t always clear in what we do as a business to support this mission of changing the world one building at time. 

To help illustrate the offerings at Melink, pretend you own a hotel, restaurant or operate an entity involving a commercial kitchen facility.  Prior to leaving for work, you utilize your smartphone to check your building’s health for your employees and customers by swiping open your PositiV app. You check the latest building health makers for indoor CO2, temperature, humidity and building pressure.  The building pressure has been trending negatively for a week and notify your Melink Test, Adjust, & Balance account manager.  Next, you request an investigative visit to determine the root cause and next steps for corrective measures.  Upon arrival, a field-technician identifies the outside air damper on your RTU has been locked shut.  An insufficient amount of fresh outside air is being supplied to your building. 

This negative air pressure situation would have been substantially worse; however you have Intelli-Hood. A demand control kitchen ventilation system that adjusts exhaust fan speeds to cooking demands.  Your Intelli-Hood control system automatically turns on in case the prep crew starts cooking without the fans. It also preemptively warns your team if there’s an issue with the exhaust fan to mitigate risk from fire.

Knowing your building is back to optimal conditions you head to the back office. You start to review your utility bill statements and prepare payments.  You’re shocked at the 40% electrical bill decline. Then you remember the newly installed and commissioned HVAC rooftop unit.

Welcome to the Melink Umbrella.  Not all customers can benefit from the full suite of offerings, but these services make us a stronger partner for our customers. They invest in business growth in a responsible, sustainable manner, help us change the world, one building at a time. 

When Should My Building Be Balanced?

A proper air balance within a building is an important factor for providing a healthy and comfortable indoor environment for occupants.  Like many other critical building systems, the air balance must be maintained over time, and isn’t something that you can simply “set and forget”.  So then, when should a building be balanced?  Here are some common events that would trigger the need to perform an air balance.

New Construction:

Every building that has some form of HVAC system (heating, ventilation, and air conditioning) should be balanced when it is first constructed. By this, I mean that the HVAC systems should be inspected, tested, and adjusted to ensure that they are operating correctly, efficiently, and as intended by the design engineer and as expected by the building owner. A balanced building will provide a comfortable and healthy indoor environment for the occupants, delivered in an energy efficient manner, and will have a proper positive pressure. Select a TAB professional to perform the air balance who is objective, meaning that they are hired directly by the building owner and are independent of the installing contractors and equipment manufacturers, who is experienced in your particular type of building and HVAC systems, and who is certified by an industry-recognized accrediting agency, like NEBB or AABC.

Remodel:

The building should be rebalanced during any major remodel event, such as expanding the building or changing the functional use of a space within the building. This is important because the HVAC system was originally designed and balanced for specific use conditions, and when those conditions change, the system will need to be readjusted. Be sure to consult with your mechanical design engineer prior to the remodel to verify that the existing HVAC system can handle the new demands. The building should also be rebalanced anytime elements of the HVAC system are modified or replaced, such as when ductwork is rerouted or when aged equipment is upgraded. This is important for verifying that the new equipment is installed correctly, operates properly, and is adjusted for the design conditions. For a building that has cooking operations, it is important to also rebalance whenever the cooking appliances are relocated or replaced with equipment of different use or heat load, such as replacing an oven with a fryer. This is significant because a kitchen ventilation system is designed for a specific bank of appliances. When the appliances and cooking operations change, the ventilation system will need to be adjusted to ensure it correctly captures and contains the heat and effluent produced.

Periodic Tune-up:

Even if a building has been balanced during the original construction, and it is not undergoing any remodels or equipment replacements, it should still be rebalanced periodically. This is because the performance of the HVAC system can change over time due to normal use and wear and also due to adjustments made by operations and maintenance personnel. Examples of this are when an operator switches the fan mode of the thermostats from ON to AUTO or when a service technician closes the outside air dampers in a rooftop unit in an attempt to fix a comfort complaint. For the complete building HVAC system, I would recommend a proactive rebalance frequency of every two to three years. This will ensure that the systems operate effectively and efficiently throughout their lifecycle and will help prevent the very costly issues created by having a building out of balance for a prolonged period of time.

Want to understand more about air balances? Read about air balance basics for existing facilities, watch our video on how an air balance works, or contact us to learn more!

Top 3 Points to Consider Before Scheduling a Balance

  • HVAC equipment is installed and operational.

This one seems like a no-brainer, but there are always occurrences when Melink arrives to perform a balance and necessary equipment either hasn’t been installed or isn’t properly operational. Examples might include VAV’s or dampers that haven’t been installed, or a RTU that isn’t operational.

Ensuring that all ductwork has been completed, balancing dampers are properly installed, any grilles, registers and diffusers are installed, and the RTUs have clean filters helps make sure that Melink can provide a proper air balance, as well as mitigate any potential return service costs. Making sure that all equipment (especially RTUs) has undergone a proper start-up to confirm power should always be completed ahead of Melink’s arrival.

  • All HVAC equipment can be easily accessed.

Another hindrance to any proper test & balance is not being able to access the necessary equipment. This includes equipment installed inside the building, as well as equipment on the roof. When working with a customer located inside a mall or shopping center, security and approved roof access becomes another added component that must be considered.

Melink typically requires assured access to all applicable HVAC system equipment, including RTUs, VAVs, Exhaust Fans, dampers, etc. Access to fully open dampers, ceiling-height diffusers, and thermostats that may be in an office is necessary to properly complete the balance. Our Account Coordinators will also discuss roof access, security measures, and accessibility to ladders or lifts.

  • Allotting adequate time (2-3 weeks) to schedule and complete the balance.

Though some seasons are busier (or slower) than others, our goal at Melink is to provide every customer the same level of service excellence no matter the time of year. This includes communication with the customer, scheduling the site visit with one of our National Network technicians, performing the balance and working with the customer on any punch-list items, and finally, providing a certified test & balance report.

Our team of National Account representatives and technicians work with the customer through each step of the process. Scheduling service with Melink approximately 2-3 weeks out from turnover will help to ensure a proper and complete balance, and enough time to work through any punch-list items or lingering comfort issues for the customer.

Want to learn more? Contact us today!

Customer Experience – The Key Differentiator

Good is no longer good enough! It seems it was only yesterday that every business claimed the key to winning customers was the quality of product or service they deliver. Here at Melink, we’re changing the game to focus on the customer experience! According to a Walker study, by the year 2020, customer experience will overtake price and product as the key brand differentiator. So, what is customer experience you ask? Customer experience is your customers’ perception of how the company treats them. These perceptions affect their behaviors and build memories and feelings, and may drive their loyalty. In other words, if they like you and continue to like you, they are going to do business with you and recommend you to the others. With customer experience being the new battlefield, companies are changing their approach, offerings, and business practices. Sales teams are working harder to learn their customers and their customer’s business, so they can create the “wow”. Hotel managers, restaurant chains, and even doctors’ offices are focused on creating an experience that knocks their customers socks off, instead of just standard practices.

These days, social media gives the consumer a lot of power and impact. There’s an instant feedback loop and the cluster of data starts to create the company’s reputation. For example, if you get on Amazon to buy a new bike for your son, you’re likely going to check the performance stars and the customer reviews. Any of those reviews can be the difference between you purchasing that bike and moving on to a different bike. If you’re looking for a surgeon and every website has them at 3 out of 5 stars, you’re likely going to move on to the next guy. He may be the best surgeon in the land, but his rude receptionist and office staff have poor bedside manner and make people miserable when they go in to see him. If you go to a fast-food burger joint, how likely is it that you’re going to write a positive Yelp review if you pull up to the drive thru, order your food, pay the correct amount, get the correct change and correct order, and you leave in a timely manner? Probably never! They didn’t go above and beyond and create the “wow”! If you want to improve the customer experience, there must be a “wow”! Recently I went through a drive thru myself and was caught off guard with my experience. When I pulled up it was raining. Normally I would get soaked reaching out to hand over the money. This time the cashier stuck an umbrella out the window, so I wouldn’t get drenched. Super small, super easy, but I was impressed! I’ve never seen it before in my time on this earth and he was focused on my experience! I did write a review and I tipped a drive-thru cashier for the first time!

Millennials are changing the game and companies need to embrace it. Sure, the entitlement is out of control, but the business practice changes are not all bad. If you’re focusing only on your product or service and not how your customer feels about the entire experience, you’re in trouble! Some of the large hotel companies are incentivizing their General Managers on customer experience and guest loyalty. The baby-boomers want to talk, interact, have face-to-face experiences with nice people. The millennials want to check-in swiftly to the hotel with no hiccups and have issues resolved quickly. Management needs to address all their consumer personas in a unique way to setup the individual customer experiences for success.

What happens if you fail to provide a positive customer experience? According to a recent study, 67% of customers mention bad experiences as a reason for churn and only 1 in 26 unhappy customers complain. That means companies not focused on the customer experience will lose customers well after it’s too late! Most of this is the result of what I refer to as “sales autopilot”. When you’re there trying to make it look like your product is perfect for them, without the data, you end up losing trust with them. Trust, brand and customer experience are all built on honesty. And honesty is knowing when your product won’t be a perfect fit for everyone. Therefore it’s so important to stop selling and start solving!

Since most companies will be expected to compete mainly on customer experience, organizations like Melink that focus on customer experience will stand out from the noise and win loyal customers over. One thing is for sure, if you want your customer to have an excellent customer experience and create a “wow” you must know your customers better than ever before! Here at Melink, my team and I are completing customer profiles and personas to improve individual experiences. Once you know your customers well enough, you can use that knowledge to personalize every interaction. Customers these days have more power and choice than ever before. Thus, we are responsible for understanding and acknowledging their needs. When people ask what we do, it shouldn’t be Test & Balance, Demand-Controlled Kitchen Ventilation (DCKV), Solar, or Geothermal, it should be creating the best customer experience in renewable and energy reduction markets for our customers!

The Test and Balance Professional

The HVAC industry is vast; there are many products and services that make up the build of any one system. Test and Balance is a very important niche of the large HVAC industry. Many HVAC companies have offered test and balance services throughout the years, but very few of them have employed technicians dedicated specifically to Testing and Balancing. Enter Steve Melink, circa 1987. Steve knew there was a service gap in the HVAC industry and addressed it. Does it really make sense for an owner to allow an installing contractor to verify the HVAC system they installed is correct? Would it not make more sense if an INDEPENDENT, CERTIFIED and SELF PERFORMING entity verified that the mechanical engineer’s design was met? Of course, it would!

Fast forward 31 years and Melink Test & Balance is still going strong thanks to our dedicated team of technicians. These Balancing Professionals are dedicated to Melink Corporation’s core values of Integrity, Innovation, and Service Excellence.

What is a Test & Balance Technician and What Do They Do??

Our National Network consists of more than 30 professionals across 19 states. Our technician tenure’s range from 15 years to less than a month! 100% of Melink balancers are NEBB trained with more than half of the network being NEBB Certified Technicians. Our technician’s experience prior to Melink varies from HVAC service technicians to general contractors to aircraft systems mechanics. Our team currently services more than 50 major accounts and we are adding more every year. As you can imagine, Melink Technicians have seen nearly every type of commercial HVAC unit utilized by the commercial retail market. There is no typical ‘day in the life’ for our T&B technicians. Between the location, business type, and scope of work, every week is a new adventure!

The lifestyle of our techs is unique, but very rewarding and profitable. All techs are road warriors, traveling across the United States each week to different jobs. Melink covers all travel expenses and supplies each tech with a company vehicle. Not only does this allow the team to see the U.S. on the company dollar, but their personal expenses decrease since most of the week they are being covered by the company. Food, gas, and vehicle expenses add up!!

This position is also very independent and needs a disciplined self-starter. With most projects only needing one tech, most of the travel and work is done alone. Even so, the Melink National Network is a family. Each tech knows that a fellow balancer or office support is only a phone call or an email away if they are ever in a tight spot. Even after hours, our technicians constantly interact with one another to help each other grow and support our customers. This is not just a career or a steady job, this is a lifestyle.

On top of it all, our technicians are also partial owners of the company. Melink Corporation is now an ESOP (Employee Stock Ownership Plan), which gives all Melink employees even more incentive to push the envelope with innovation and succeed as a business. Thanks to our National Network Technician team, Melink Corporation has been listed as a Best Place to Work for 3 consecutive years. Melink Corporation encourages input and recommendations for improving the business and improving the lives of the technicians. Melink works hard to address everything to better the position and the experience, for our employees. Striving for the best possible work/life balance is something very important to Melink Corporation.

One can find challenges in any profession they choose. But Melink’s National Network chooses to be challenged on a daily basis and to thrive in it! Their dedication and their commitment to service excellence is the backbone of Melink T&B!

Click here to learn more about Melink T&B.