To maintain the aesthetics of a new roof design, building owners often choose to conceal their rooftop mechanical equipment with screen walls. Screen walls are considered “architectural walls,” and are typically constructed using steel frames and finished with metal wall panels.
While aesthetics are an important consideration for screen wall design, building owners and designers should not overlook wind loading while selecting metal wall panels for their screen wall. Metal wall panels are often secured to a solid substrate, such as a masonry wall; however, wall panels attached to exposed steel framing (vertical posts and horizontal channels) in screen wall applications typically leave the back side of the panels open and exposed to wind. Wind can create a negative pressure acting outwards from behind the panel. This wind load pressure can cause panels to bow, allowing the connection between panels to disengage. When selecting metal wall panels for a rooftop screen wall, consider the following parameters:
- Panel Width: Increasing the width of a metal wall panel increases the surface area on which wind loads are applied. Selecting narrower metal wall panels helps to mitigate the effects of negative wind loading pressure.
- Panel Material: Many manufacturers offer metal wall panels in a variety of materials including aluminum and steel. Thicker gauge material with higher tensile strength will reduce the tendency for panels to deform under negative pressure.
- Panel Profile: Metal wall panels come in a variety of profiles: panels typically consist of two engagement legs on either side of the panel that interlock to form a connection between adjacent panels. Panels with longer engagement legs will provide for a deeper connection between adjacent panels, limiting the possibility of this connection to be compromised under wind loads.
Installing metal wall panels on a rooftop screen wall can improve building aesthetics; however, without proper consideration of wind loads, these panels are susceptible to damage. Selecting metal screen wall panels of an appropriate width, material, and profile to withstand wind loading pressure will help the panels to remain secure throughout the life of the roof.
In today’s health-conscious and eco-friendly world, the popularity of organic products is on the rise. This interest and concern has carried over to Athletic Facilities Planning. Gale recently completed a project for a school opting to use organic infill for two new synthetic turf fields. The school was focused on the fields’ proximity to wetlands, as well as the health of their students and the perceived concerns associated with SBR crumb rubber. The school was provided with a summary of alternative infill options and Geofill, a coconut/cork and sand mix, was selected.
The School District felt this decision was appropriate after weighing the pros and cons of the infill options and costs. Below are some considerations for organic alternate infills:
- Organic and environmentally friendly.
- Retain water, which provides an evaporative cooling effect as compared to fields with a crumb rubber infill. This can be an advantage, especially in warm climate locations.
- Provide athletes with a natural feel under foot.
- Shock pads provide a consistent G-max (acceptable impact level).
- The cost is higher compared to traditional crumb rubber field (40% increase for infill and shock pad).
- Can require more maintenance than crumb rubber.
- Requires replenishing every 2-3 years.
- The material is not recyclable for infill use, but can be used for landscaping beds.
- May require watering since it can become dusty during a dry summer.
At one time or another, every building owner will deal with the process of replacing their roof. While this is a necessity for the proper function of a building, it can often be costly, disruptive (smelly and noisy), and messy. If your building currently has a metal roof that needs replacement, one option to consider is a metal roof overlay system.
The most common metal roof overlay system includes prefabricated sub-purlins, which are z-shaped structural members that are factory cut to fit snugly over a variety of metal panel profiles. The purlins, typically 16-gauge galvanized steel, are attached through the existing metal roof panels to the building’s structural frame to provide the appropriate base to which the new metal panels are secured.
The benefits of a metal-over-metal retrofit roof system include:
- Reduced costs and disruption associated with demolition, and provides better protection for the building’s interior finishes from unpredictable weather versus removing the existing metal roof.
- Minimized requirements for the contractor to gain interior access, which reduces interruption of occupant day-to-day activities.
- Increased energy efficiency. The sub-purlins can be formed to customized depths to allow installation of additional insulation.
- Reduced labor costs from faster project completion.
- Ability to easily upgrade an existing exposed fastener (face fastened) metal roof to a more watertight standing seam (concealed clip) roof.
There are many factors to consider before choosing a sub-purlin retrofit system. The existing building structure should be analyzed to verify that it can safely support the additional weight of an overlay. Furthermore, applicable code requirements should be researched to determine if the new overlay system will be compliant. Lastly, the overall condition of the existing metal roof system and insulation assembly should be evaluated. If the existing panels are visible from the interior and are aesthetically unpleasing, or if the need for continuous insulation is driving your roof project, an overlay may not be the right option.
When planning an athletic facility project, it’s important to keep in mind the overall project timeline. Prior to bulldozers and excavators moving dirt, an engineering process that can take months to complete must occur. While each project is different, below is a typical project process and timeline:
The FAA is offering a $500 rebate to general aviation aircraft owners to aid in the cost of Automatic Dependent Surveillance – Broadcast Out (ADS-B Out) equipment. Starting in 2020, this equipment will be mandatory for flying in most controlled airspace.
The ADS-B Out requirement is part of a transition from ground radar and navigational aids to precise tracking using satellite signals. The equipment periodically broadcasts an aircraft’s position, velocity, and other information including dimensions. Displays utilizing ADS-B Out are capable of showing other aircraft in the sky or on the ground at an airport. It can also provide pilots with information on hazardous weather, terrain, and temporary flight restrictions. Only certain features are required by the ADS-B Out 2020 mandate. Title 14 CFR §91.227 defines the equipment requirements.
The FAA plans to issue up to 20,000 rebates on a first-come, first-serve basis for up to one year. This incentive is only for registered, fixed-wing, single-engine piston aircraft. Software upgrades to existing equipment are not covered by the rebate. For additional information on rebate eligibility, equipment installation, and to reserve and claim a rebate, visit http://www.faa.gov/nextgen/equipadsb. A full description of the airspace covered by the mandate can be found in Title 14 CFR §91.225.
The scientists at the National Oceanic and Atmospheric Administration’s (NOAA) National Hurricane Center have predicted that the 2016 hurricane season will be more active than in the last three years. We have learned from experience that hurricanes can be quite unpredictable, causing widespread damage to many vulnerable areas, and are not limited strictly to coastal regions. Depending on the ultimate path and intensity of a storm when it makes landfall, hurricane‐force winds can cause loss of power, flooding, and damaged or destroyed roofs, doors, windows and wall systems. This could lead to substantial interior and or structural damages to buildings. These storm-related building failures can cause unanticipated shutdowns of educational, institutional and commercial sectors within a community.
The following preventive measures may help avoid or reduce catastrophic harm to your building’s components and systems, and improve the chances of your facilities maintaining functionality in the event of a hurricane:
Reliable Back‐up Power & Resources. Stockpile resources, such as generators, batteries (alkaline, rechargeable, car, solar voltaic, etc.), a reliable supply of fuel, water, flashlights, radios, portable televisions, power inverters, roof repair materials, removable shutters, tarps and any other essential items in a secure location where they can be quickly retrieved after the storm.
Protect the Roof. Inspect the entire roof thoroughly before storm season. Secure areas of displaced membrane or perimeter flashings by installing additional anchors, especially in older buildings that have not been designed to meet current wind code requirements. Install additional fasteners or screw anchors with washers on the face of the edge metal or coping face flanges, with the highest priority being at corner zones and about 24‐in. on‐center in the perimeters. Add mechanical fasteners to membranes in vulnerable perimeter areas where adhesion of the roof system is suspect.
Mitigate Stormwater and Flooding Concerns. Remove debris or loose materials that could clog drains, gutters, downspouts and scuppers to maintain free flow of water. Relocate or reposition critical materials, such as scientific experiments, records and archives, key computers, etc., away from areas that may be prone to flooding.
Secure Roof Appurtenances and Accessories. Basically, anything that is anchored to a roof needs to stay there. Reinforce or secure air‐conditioning equipment and fans to the roof using additional screw fasteners and/or straps. Add metal or even nylon straps at strategic locations to help reinforce the ducts and provide supplemental anchorage down to supports.
Safeguard the Building Enclosure. Minimize potential damage from windborne debris and to the building’s exterior by using storm shutters (preferred method), plywood panels, steel deck material or lightweight corrugated plastic materials to protect windows, doors and louvers (wall openings). Window films applied to the inside of the glass can provide a level of protection, but its use should be limited to upper floors, as films are generally not tested for large projectile resistance. Secure or bring in light-weight objects, such as garbage cans, tools or furnishings that may become projectiles during a storm.
Implement a Facility Survival Plan. Creating a plan before the storm will help you to quickly mobilize and make necessary repairs to restore operations as soon as possible. Below are some important steps to consider:
- Establish a base of operations from which to coordinate recovery and repair efforts.
- Develop a contingency plan that focuses on readiness, including manpower, equipment and materials needed immediately after the storm.
- Organize a recovery team by assigning repair tasks to specific individuals or contractors prior to the emergency. Include team member phone numbers and email, as well as team staging and assembly locations. For each roof or wall assembly, specify materials, protocols and personnel responsible to address problems. Use a chart or calendar to establish a timeline for required repairs. A repair manual will also be helpful and allow for consistent quality standards during the recovery operation. Roof and wall repairs should be completed by a contractor knowledgeable about proper flashing techniques and materials.
- Develop a primary and backup communication protocol with post-event procedures for on-call constructors, consultants or other entities to expedite emergency assessments, evaluations and repairs; to temporarily relocate assets or functions; and for potential transportation needs.
Did you know that a half-inch space is all a bat needs to crawl into your roof? A space the size of a bottle cap is all it takes for them to begin causing havoc. The presence of bats in a building can affect the replacement process and add costly repairs in an existing building.
Some species of bats are endangered and protected, while others are just disruptive. It is important to consider how to resolve the problem of evicting them from the habitats they create in your
structure, and to understand the laws in place to protect
them, and what measures must be taken to relocate them.
Bats are an important part of our ecosystem. They consume a vast amount of insects including some that damage agricultural crops, they
pollinate valuable plants, and their waste can be a rich natural fertilizer;
however, bat guano in your building is not pleasant and can be environmentally hazardous.
One major issue bats can cause is staining in the area they enter and exit a facility. This is due to waste accumulation, and can ruin building insulation, sheet rock or particle board, cause an unbearable smell and in extreme cases may cause structural damage.
Tall structures are ideal locations for bats because higher elevations are less likely to receive maintenance. Facility owners seldom notice small cracks or gaps on the facades of higher buildings, but that half inch crack in a mortar joint 30 or 40 feet off the ground can become a highway for bats to enter a structure. Once they gain access to your space, getting them out is a costly and a time consuming endeavor and depending on the location, it can interfere with day-to-day operations.
Because some bat species are protected, a professional should be utilized in the removal process in order to relocate them to a safer area that does not cause harm to you or the environment. Usually this is done through a process called bat exclusion, which lets them fly out, but not back in. This process is performed at night when bats leave to find food. A professional will need to determine the proper enclosure required repairs to prevent them from coming back and assist in the preparation of a maintenance program.
Inspecting your building and knowing what to look for is a crucial step in maintenance and avoiding this problem. At a minimum, become aware of what natural habitats are present in your surroundings. This will help determine what kind of inspections are required. Some important points to consider are:
• Training maintenance personnel on the warning signs of bats
• Incorporating a systematic documentation process to know what to look for on a daily, weekly or monthly basis
• Communicate any bat findings with professionals trained in the relocation process
Once bats or other critters find their way into your building, many issues can arise. Not only do you need to get them out, but the clean-up can be tedious. Next time you spot that small “insignificant opening” in your building, don’t ignore it, you never know what’s inside or what species wants to make it the entrance to their new home!
Take some time to view the links below for more information:
Many involved with aviation are aware that pointing lasers at in-flight aircrafts can be a serious, if not deadly, issue. The FAA and the justice system have been taking serious action against violators of FAA policies banning the practice of striking aircraft with lasers. Violators are given heavy jail sentences upon conviction (a 26 year old man in California was sentenced to 14 years in federal prison), and the FBI is currently offering a $10,000 reward for information leading to the capture of a recent violator.
Click here for additional information on this serious subject. This FAA page includes articles detailing laser-related arrests and convictions, an FBI video on the dangers of pointing lasers at aircraft, and a consumer safety alert on purchasing lasers.
New England winters, as evidenced by 2010/2011 and 2015, can deposit large amounts of snow on roof areas and potentially overload the roof structural system. Snow tends to accumulate against rising walls and parapets, rooftop units and roof wells, and can cause large concentrated loads on roof areas. Original building structural drawings often express the snow load that the roof was designed for in pounds per square foot (psf). This doesn’t directly correlate to a depth of snow. The allowable depth of snow depends both on the design load psf and the unit weight of the snow in pounds per cubic foot (pcf). The Massachusetts State Building Code (MSBC) and associated references provide an equation for the unit weight of snow based on the design ground snow load; however, the actual conditions may vary depending on the weather.
We suggest the following procedure for measuring roof snow loads:
1. Measure the depth of snow at various locations around the roof area. Pay particular attention to accumulated snow against rising walls or mechanical units where snow tends to drift. We recommend using a plastic shovel to dig down to the roof system to avoid damage.
2. Using a known volume such as a stove pipe of known diameter and height, obtain a sample of snow in its existing condition. A stove pipe can be used to slide through the snow and then cap the bottom of the pipe to collect the snow.
3. Measure the weight of the sample snow (remember to subtract the weight of the stove pipe or similar apparatus).
4. The unit weight of the snow will be determined by dividing the weight of the snow by the known volume. We suggest performing the measurements at multiple locations on the roof, including where the snow appears to be consistent depth and at drifted snow locations as the unit weight may vary.
5. Once the unit weight is obtained, divide the allowable uniform load (obtained from the original drawings) by the unit weight to provide an allowable snow depth. For example, if the design or allowable snow load is 30 psf and the unit weight of snow is 20 pcf, the allowable snow depth will be 30/20 = 1’ 6” of snow.
6. While performing the measurements, be aware of any ice, slush or water below the snow since these are generally heavier than the snow. These layers should be weighed separately and added to the snow load.
An important first step in completing an athletic campus needs assessment and master plan is the sampling and agronomic testing of fields’ root zone materials to evaluate soil structure, organic content, micronutrient levels and pH. Testing is a key factor in developing the proper maintenance or rehabilitation strategy for improved turf growth.
Over the years, Gale has observed a significant trend in our testing results. Athletic fields, particularly in northern New England, tend to be more acidic. These fields must be maintained to hold up under substantial use, requiring considerable planning and maintenance to sustain their soil quality. Over the past two years, we have documented and recovered soil samples with an average pH of 5.2, and with individual values below 5.0. This significant level of acidity results from the gradual breakdown of indigenous plant materials in the soil, and is exacerbated by the influence of acid rain.
Why should we be concerned with this?
According to the Massachusetts Natural Resources Collaborations (Mass NRC), the pH of the soil directly affects the amount of nutrients available to grass cultivars. Cultivars are varieties of plants produced in cultivation by selective breeding. They can ingest the wrong nutrients when pH levels are not optimal. Preferred nutrients are most accessible when the pH is in the range of 6.0 to 7.0. With average pH ranges consistently below 5.5, regardless of the fertilizer regimen, turf grass is often starved. For example, Kentucky Blue Grass blends, often selected for athletic turf grass based on their restorative capacity due to their rhizome generation, cannot prorogate as intended and fields break down under normal use.
How can we fix the issue?
Lime! The UMASS Department of Agronomy provides specific lime application strategies for each soil sample tested. While there are multiple considerations for crafting a pH adjustment strategy, low pH root zones with values less than 5.4 generally call for lime application rates of up to 150 pounds of limestone per 1,000 SF, applied at a rate of no more than 50 pounds per spring or fall season. For a typical 90,000 SF multi-purpose rectangular field, this amounts to 4,500 pounds per season for three consecutive seasons. In summary, test the soil and be prepared to apply lime for a happier, healthier natural turf field.