Category Archives: Design

Buying Direct or Through a Contractor? What’s Right for You?

On both large and small commercial pool construction projects, owners have multiple options when it comes to purchasing operating equipment. Most commercial swimming pools are designed and constructed “turn-key,” meaning everything needed to run the pool is provided by the contractor as part of the construction process. This includes items like first-aid kits, lifeguard stands, and the first 30-days worth of pool chemicals. chemBut turn-key is just one of many delivery methods. Another popular method involves owners purchasing items directly from wholesalers or manufacturers. Like most aspects of the construction process, the sooner this is communicated to the design team, the better.

Pools are delivered to the owner turn-key because it helps the project get through the construction review process. Local health departments and other review entities will want to verify that all necessary maintenance and safety equipment is on-hand when it comes time to open and operate the facility. If an owner purchases directly, these items typically still need to be included in the construction documents to obtain necessary building permits. Owners should coordinate with their designers to ensure health departments and building authorities understand that requirements will be met.

Purchasing Direct:

  • Allows owners to specifically choose their products. Often times, general contractors supply the lowest bid product. If you prefer one product over another, purchasing direct allows you to make that decision for yourself.
  • Allows owners to easily provide input on quantities of product while placing the order. This is a big draw for facilities with limited storage space.
  • If done right, purchasing direct should save the owner money. Contractors sometimes mark up products as part of the construction process.

Items Typically Purchased Direct:

  • boardLarge play features like waterslides and aquatic play structures. These are typically installed by the manufacturer regardless of who purchases it.
  • Scoreboards in competitive venues.
  • Maintenance and safety equipment.

Why Turn-Key Might Be Good For You:

  • Purchasing direct requires a lot of research to ensure you’re purchasing the right items. Additionally, it requires you to be budget and spending-savvy so your purchases are good things for your bottom line. Contractors tend to have the in-depth technical understanding or prior experience necessary to make smart product decisions. This isn’t always the case for facility owners.
  • Purchasing direct also requires negotiation skills to secure fair pricing. Without a skilled negotiator or buying power, the process can lead to higher costs and lower-quality products.

Don’t think you can do this on your own? Hire a professional to help you navigate the process. With a professional, you often gain negotiating power as part of a larger entity. This should automatically qualify you for prices that even the most skilled negotiators will not be able to obtain. Look for a professional that has a wide range of supplier relationships and has your best inerest at heart when it comes to operations products.

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What Are Natural Swimming Pools?

At a time when people, more than ever, are aware of the dangerous chemicals associated with products they use every day, it’s no surprise that this consciousness has made its way into people’s thoughts about the places they spend their time. When taking a dip in a pool, swimmers know that chlorine and other chemicals are used to keep the water safe and clean from harmful bacteria. But as concerns rise regarding the effects of prolonged exposure to these chemicals, people tend to look into what alternatives are available. One common alternative that comes up is the natural swimming pool.

While a relatively new idea in the United States, natural pools have been seen in Europe for decades. The first natural swimming pool was built in Austria in the 1980’s. The private pool began to gain popularity, and the first public natural swimming pool was built in Germany in 1998. Now, there are over 20,000 private and public natural pools in Europe. In recent years, we have started to see this trend gain traction in the United States, with many choosing to add natural pools in their own backyards. Due to regulatory reasons, natural pools have really only been developed for residential, private use. However, last summer, the very first public natural swimming pool opened in Minneapolis, Minnesota. Due to the strict chemical requirements of public pools in the United States, this project required many layers of approval from the state legislature to become a pilot project for this type of pool. Should the project prove successful and efficient, we will likely see more natural pools in the United States in the near future.

nat grapicNatural pools consist of two areas: the swimming pool and the regeneration zone. These two spaces can be located directly next to one other or in completely separate areas. The pool works by filtering water through biological filters before reaching the regeneration basin. Natural gravity can drain the water to the regeneration area, or pumps can be utilized to send the water to the basin. The regeneration zone consists of plants which create an ecosystem to clean the water. The plants and gravel in the basin help remove any harmful bacteria from the water before it is pumped back into the main pool area. Pool skimmers are also often used to keep the water surface clear of debris.

The primary advantage of natural pools is that there is no chemical use, which can lower maintenance costs. Additionally, the regeneration area can serve as a home for some wildlife. However, where there are advantages, there are also drawbacks. Projects like this often require a larger footprint than a typical pool due to the regeneration zone. Project scale should always be considered. Additionally, it can take some time for the artificial ecosystem to take effect. This initially could cause issues with algae and other organisms running rampant in the regeneration zone. But after time, this problem diminishes. Natural pools tend to have a more greenish color than traditional swimming pools, which can be concerning for some swimmers. But, swimmers who are used to the crystal clear blue of traditional swimming pools can swim assured knowing the natural pool is keeping the water clean and safe for them to enjoy.

Whether a natural swimming pool is designed to look like a pond or a traditional pool, users can enjoy an experience that is new and unique, yet familiar and enjoyable.

Which Project Delivery Method is Right for You?

One of the major items often misunderstood on a construction project is the delivery method. Traditional project delivery methods include design-bid-build, design-build and Construction Management.

Historically, the design-bid-build process has been the most common project delivery method for large scale commercial projects. Under this delivery method, the owner holds separate contracts between the ddeliveresign professionals and the construction team. This delivery method is most common amongst publicly-funded projects.  The design team (including traditional building architects, landscape architects, MEP engineers, structural engineers and aquatic design professionals) works directly for the owner to develop a set of construction documents. These documents are then used to create a competitive bidding environment between multiple vendors, manufacturers and suppliers.

The teaming circumstances between the design professionals and the installing contractor are different under the design-build scenario. Under this delivery method, the design-build team is led by the building contractor. The design professionals are then contracted through the building contractor, thus providing the owner with a single point of contact for both the project design and construction.

del 2In design-build, the contractor traditionally works with the owner on the development of a Guaranteed Maximum Price (GMP) based upon partially-developed plans. Design-build can, under certain circumstances, provide opportunities to expedite the overall project schedule. The owner should request that GMP drawings be as complete as possible, and participate in the development of the GMP package to minimize surprises with the pool and any support buildings. While initial construction costs can sometimes be reduced through a design-build process, the owner must be wary of cost-cutting measures that can decrease the lifespan of the facility and increase yearly operational cost, both of which are bad for the owner of the facility.

In the Construction Management project delivery method, the owner typically holds separate contracts with the construction manager, the design professional, and in some cases, the installing contractors. Construction management can either be performed “at-risk” or “not-at-risk.” When not-at-risk, the construction management agency (CM) typically becomes the owner’s representative by managing the project from the back end of design through construction.  In this scenario, the CM does not directly hold a contract with any specific contractor. When at-risk, the CM typically commits to a GMP prior to construction and acts as not only the owner’s representative, but somewhat equivalent to a general contractor during construction. If the owner does not possess knowledge or experience in construction projects, the inclusion of a CM in some fashion can benefit the overall process for the entire team.

Once you have chosen your preferred project delivery method, it’s time to think about the process for selecting your design and/or construction professionals. Several tools are available to assist owners when determining the best team to help create the desired facility. These include Letters of Interest, Requests for Qualifications (RFQ), Requests for Proposals (RFP), and the Interview process. These tools can help determine the proper team who will create and manage the project from start to finish.

Cast-in-Place vs. Shotcrete Concrete Pool Installation

For many, the question commonly arises as to what type of concrete material makes the best watertight vessel: cast-in-place concrete, shotcrete or gunite. While each have their own strengths, one must consider key items such as geographical/site location, soil conditions and most importantly, availability.

There are many locations in the United States where shotcrete and gunite are not produced. Soil conditions can also play an integral role in the decision making. Questionable and/or remediated soils often call for thicker concrete placement due to the needed increase of structural steel (rebar).

The placement method utilized for concrete is to discharge it from a ready-mix truck down a shoot directly into form work or into a hopper equipped with a boom pump. The concrete is then pumped into forms and must be vibrated for compaction. By contrast, the shotcrete process, whether using wet or dry material feed, may only require single side forming or no forming at all by utilizing the earth as the back form in selected areas. This process utilizes a smaller pump with added air pressure via an accompanying compressor. The air is introduced atshotcrete the end of the discharge hose nozzle, creating a high-pressure discharge of the concrete mix. The pressure creates compaction, thereby enhancing design creativity and application flexibility, often resulting in a savings of time or money. The impact velocity of correctly placed shotcrete quickly compacts the material, yielding an “in-place” mix that’s richer in cement and higher in strength than the same mixture prior to placement. With shotcrete, what appears to be a waste of supplies, known as “rebound” or overspray, in reality ends up in thick, high-energy shotcrete as a portion of the mixture ricochets off the receiving area and away from the placement area. The loss through rebound will vary based on various factors including the dryness of the mix, the shooting distance from the surface area and wind conditions. The expected thickness is generally overshot, trimmed back to the design thickness reflected through “look-outs,” and finished to the required surface consistency and appearance. This process commonly requires more labor for multiple finishers to cut and finish the concrete and laborers to follow with clean-up and rebound removal. Compared to the additional materials and labor required to form both sides for the cast-in-place process, this can often times offset each other. However, cast-in-place does require additional labor for front and back form removal.

Characteristics of how concrete or shotcrete is delivered for pumping or placements are very similar. Typically, regardless of the concrete type, shotcrete or cast-in-place concrete has a 90-minute window from the time it is batched at the plant until it placed. Temperature of the material, air temperature and humidity levels can increase or decrease the set times of the concrete. Typically, ready-mix companies hold back 10-15 gallons of water in the mix so the contractor can adjust the slump of the concrete onsite. A concrete truck typically hauls 8 to 10 yards of concrete and 1 cubic yard of concrete typically contains 38 to 40 gallons of water. Project specifications dictate the required mix design and testing agencies commonly verify the concrete slump of the first truck prior to pumping, as well as periodically through the day. Adding 1 gallon of water over the design mix (amount of gallons of water per yard of concrete) can decrease the strength of the concrete by 200 PSI.

Often overlooked, the curing process is an integral step for optimum intended performance of concrete or shotcrete. The mix design can be perfect and the placement can be of the highest quality, but if not cured properly, adverse effects can impact the quality dramatically. While there are many methods, curing concrete or shotcrete surfaces with water is by far the best method for maintaining adequate moisture and controlling shrinkage cracks during the hydration process. After some time, the concrete starts the chemical reaction that eventually hardens the concrete. Curing vertical and horizontal surfaces with water can be easily accomplished with alternative curing methods considered due to project scheduling, the availability of fresh water and the ability to discharge the water being used. Curing compounds may also be applied to the concrete or shotcrete mix or to concrete surfaces after placement. However, these compounds can also have an adverse effect on the finish materials such as paint, plaster or tile mortar. It is suggested to consult with the finish contractor and the structural engineer prior to concrete placement to verify acceptance of curing compounds.

In closing, the question of which process is better? Well, as you can see, there are many variables to consider. While cast-in-place is better-controlled and suited for close tolerance work, it can be a less economical option. Shotcrete, if applied properly, can also provide a superior watertight vessel. Counsilman-Hunsaker’s advice? Make sure your concrete or shotcrete contractor is qualified to perform their work. Do your research. Ask for references and verify if their nozzleman is American Shotcrete Association-certified. Water test your pool prior to the placement of pool finishes. This process is detailed in American Concrete Institute 350.

Remember that pool finishes, such as paint, plaster and/or tile, are not designed to waterproof your pool. If the structure behind your finish is not watertight, your finishes will only serve as a temporary barrier.

What Makes a Pool Fast?

There are seven basic factors specific to pool design and operation that maximize the performance of swimmers and make pools fast. While they don’t exist in any order of priority, some are more essential than others.

Indoor Air Quality

Most people are familiar with the “swimming pool smell” encountered when walking into some indoor pool environments. That strong smell can even be picked up at an entry lobby before even setting eyes on the pool. The smell is actually chloramines off-gassed from the swimming pool. They tend to reside close to the water surface, which is unfortunate for swimmers, as this coincides with the breathing zone. Highly-competitive aquatic athletes are familiar with pushing their bodies aerobically and anaerobically. In either state, heavy respiration of chloramine-laden air inhibits performance. The good news: there are several ways to dramatically improve overall indoor air quality, and in turn, maximize swimmers’ performances. One involves using proper air distribution over the surface of the water. Another option is to remove chloramines at their point of formation. Medium-pressure UV systems can be installed to help maintain chloramine levels to 0.2 parts per million or less. These systems destroy chloramines during the recirculation process. With improved overall indoor air quality, swimmers’ performances and health are improved as well.

Water Clarity

Pool water must be clear so swimmers are able to see underwater. Clearly, being able to see markings and wall targets allows for swimmers to time their strokes into their turns and finishes, as well as break out from their underwater kicks. Water clarity largely comes down to maintaining ideal water chemistry and water filtration. Newer regenerative media filters on the market in the last 10-12 years in the United States are gaining popularity for projects pursuing sustainability. These filters consume considerably less water than traditional high-rate sand filters. However, they also filter down to 1-5 microns, while sand filters often only capture particulate down to the 25-50 micron range. Ideally, the water must have a turbidity level that does not exceed 0.5, measured with a nephelometer.

Temperature

It’s important for swimmers to be comfortable in the water, which means that water temperature should be approximately 78 degrees Fahrenheit. At this temperature, swimmers’ bodies will not overheat at maximum effort and stress. At temperatures much below this level, swimmers usually complain of stiffening muscles. Additionally, the body will be burning more calories to offset the colder skin temperature. At water temperatures much above 80 degrees, swimmers usually feel sluggish and experience an undesirable rise in body temperature during maximum effort. Something else for designers to consider are the hundreds, if not thousands, of spectators watching the competitive swimming event. These guests and their body height can cause slight differences in the rate of evaporation, and contribute to temperature conditions within the pool space.

Visibility

Good underwater visibility is the product of exceptional water clarity and light level above the swimming pool. For the highest level competition pools, some regulatory bodies require 100-150 foot candles of lighting over the water surface so that visibility for swimmers, as well as for the remote viewing audience, is satisfactory. This often requires direct illumination from above utilizing fixtures located directly over the water surface. With the overhead light source directed perpendicular to the water surface, light will penetrate the water medium and reflect off the white pool interior. Underwater lights increase the light level under the water surface not only as a source, but also as an enhancer to the reflected light. In this manner, it creates an ideally-illuminated environment for competitions.

Subsurface Turbulence

Subsurface turbulence can inhibit the forward motion of swimmers. This turbulence can be caused by water currents from the pool’s recirculation system, but this varies upon the type and location of the inlets. Circulation flow currents can be a problem if they exist in the bounded water volume of the race course. Of greater concern is the presence of rebound turbulence created by swimmers. This is more prevalent during starts and turns while executing underwater dolphin kicks. The turbulence reaches the floor of the pool, rebounds and returns to the surface in such a way that it interferes with the forward progress of the swimmers.

Surface Turbulence

Swimmers have long been aware of the difficulty of swimming through rough water as compared to a smooth, flat surface. It’s this basic understanding that led to the development of floating lane line dividers, and subsequently to the wave-quelling designs used today. Floating lane lines absorb and contain wave energy created by swimmers within each lane. The primary benefit of contemporary lane lines is to isolate the turbulence in one lane, and impede it from crossing into adjacent lanes.

We also tend to see the dissipation of surface turbulence inside the lane where swimmers have created agitation. Essentially, when swimmers swim down the lane, they create surface turbulence that impacts their speed when returning through the original point of dissipation. As a result, the swimmer experiences greater impedance at the first third of each length, with the exception of the first length. Conversely, the least impedance occurs in the last third of each length when the surface has experienced the longest period of time from the last surface agitation.

Psychological Influence

Psychological impact is a subjective variable that positively or negatively influences all athletes at the start of a race. While the mental attitude of swimmers cannot be influenced directly, there are several things designers can do to heighten the excitement and adrenaline levels of the athletes.

Design architects should educate themselves about the procedural experience of competitors. There are identifiable psychological impact points from arrival at the facility, to locker room preparation, to warm-up routines. Energy builds up as more and more athletes arrive, and as the start time draws nearer, there are behavior patterns each competitor carries out. Typically, we see competitors isolate themselves, meditate and concentrate on the task ahead of them. Privacy may be an empty room, a corner under the stands or simply a towel over the head. For high-end competitions, a ready room is provided. The location, design and appearance of this room can be a huge motivating factor for swimmers.

Conclusion

If all of these environmental conditions come together just right, your facility will understandably be known as a “fast pool.” Swimmers will be capable of reaching their full potential, and you’ll see more personal best and record-breaking times at your facility.