At American Pavilion, we provide clear span tent structures manufactured by Losberger and Hocker. By offering temporary structures from both of these trusted brands, we're able to better accommodate the unique needs of our clients. A Losberger clear span tent and Hocker clear span tent share the following qualities:
As the name suggests, clear span tents are free of physical obstructions such as interior support columns. They contain a broad, open area for your event with nothing to distract from the view, obstruct your guests’ line of sight, or interfere with placement of equipment such as stages, tables, booths, seating, or projects in construction tents.
Our clear span tents are supported by beams made of aluminum, and our thick vinyl fabric coverings are fire-retardant, flexible, and manufactured in-house. All tents are able to withstand high winds and conform to all safety requirements of the International Building Code for temporary structures. Our structures can withstand inclement weather and stay installed in the same spot for years. Almost no maintenance work is required to enjoy use of a Losberger or Hocker tent for months upon months.
Clear span tents are attached to the ground with long steel stakes rather than guy lines or ropes. This gives it a clean and sophisticated look, even from the outside. Losberger tents feature raised integrated flooring so that water runoff will be eliminated and the floor will stay dry through rainy weather.
Clients may choose to slide open wall curtains to allow good weather to shine in, or slide them closed to protect guests from inclement weather. Clients may also choose optional safety glass entrance doors and side walls that maximize views outside the tent. The glass is energy-efficient, so heat and air conditioning will stay contained in the tent.
Our tents are available in the following widths:
3 meter (10' wide)
6 meter (20' wide)
9 meter (30' wide)
12 meter (40' wide)
15 meter (50' wide)
20 meter (66' wide)
25 meter (82' wide)
30 meter (100' wide)
35 meter (114' wide)
40 meter (132' wide)
50 meter (162' wide – the largest in the country)
Because our structures are modular in design, practically any length, size, or shape can be accommodated.
Clear Span Tents - The Definitive Guide
In this guide, I will explain everything about clear span tents, from their history that began in Europe to how they are manufactured and installed. I will also discuss the vinyl fabrics used to cover clear spans as well as the engineering of the structures. Advantages of clear span tents over other fabric structures will be explained as well as the various widths and sizes. A working understanding of clear span rental tents need not be intimidating, I believe that after reading the material below, you will be comfortable discussing and renting a clear span tent structure for your specific needs.
Clear span tents (sometimes spelled clearspan) are currently manufactured by dozens of companies around the world. They are called “clear span” tents because unlike the older styled “pole” tents (think circus tents), clear span tents have no interior poles or supports. This style allows for unobstructed space under the tent structure, which in turn allows for a broad range of uses such as special events, corporate product displays, parties, weddings, sporting events, construction projects, temporary warehousing, military applications, and disaster relief. They are supported by aluminum box-beam extrusions that form the roof rafters. Once the aluminum roof rafters are assembled on the ground, they are raised using either manpower or heavy equipment like forklifts or cranes. Once these rafters have been raised, they are connected to aluminum or steel purlins, just as in traditional stick-built buildings. The rafters utilize a minimum of bolts or gravity and bayonet pins for installation and therefore may be installed quickly and efficiently. This portability and small number of parts allow for even the largest clear span tents to be reduced into parts that can be transported on straight trucks or semi-trailers. Depending on the size of a crew, their experience, and working conditions, a minimum of 10,000 square feet of clear span can be installed in a single day, and 20,000 square feet is not unusual for experienced crews. Of course, multiple teams working on a number of different tents at one time will be able to install more quickly.
These clear span tent structures do not utilize guy-lines, which are the ropes, straps, or cables that are used to supply tension to a pole-supported tent structure and keep it from collapsing or blowing away. Guy-lines require extra site space, can loosen over time, and are not as strong as the steel base plates used by clear spans. These plates are staked to the ground using steel stakes with the tent surface dictating the type and number of stakes. Soil is one of the most frequent surfaces for installations, with steel stakes driven into the ground to attach the steel base plate firmly to the ground. Soil conditions across the United States vary from sandy loam to clay. Water saturation, or lack thereof, can also significantly affect the holding power of steel stakes. Sometimes a pull test of base plates can be required at the installation site to verify that the correct number of stakes or anchors is used. Clear spans may also be installed on concrete using specialty concrete anchors. If a site does not allow ground penetrating anchoring, then in most cases ballasting (usually concrete blocks) can be used. Meticulous consideration must be paid to the proper weight used for ballasting; the tent manufacturer should be able to provide the quantity of weight required to prevent updraft and shear pressures.
Clear span tents can be installed almost anywhere, from parking lots to rooftops. A beneficial characteristic of clear spans is their ability to be mounted on uneven surfaces. The use of specialty shims or modified leg heights goes a long way in allowing for difficult terrain installations. If the terrain is too undulating for shims or adjusted legs, then reinforced scaffolding flooring can be installed and anchored to the ground, and a clear span can be installed on top of the scaffold floor. It is not unusual to see clear span tents installed dozens of feet in the air, especially at sporting events like golf tournaments where the views are paramount.
Clear span tents are weather resistant and quite sturdy. They are designed to withstand strong wind gusts and inclement weather and are one of the most weather resistant tents on the rental market. The seams in the aluminum rafters can be covered with a flexible waterproof tape and most companies utilize fabric panels to cover all rafters. These solutions aid in decreasing any possible water penetration of the roof. No tent is completely waterproof, but the ability of a tent to withstand intense weather varies depending on the type of tent. Pop-up canopies offer fair weather protection while clear span tents can withstand, in some cases, wind gusts equal to or exceeding 90 miles per hour. Those gusts are seen in the upper end of a category 1 hurricane. Despite their engineering and reliable track record, no portable structure should be viewed as a safe haven in extreme weather.
A clear span tent is available in almost any size due to its modularity. Aluminum support rafters and extensions can be added or subtracted, allowing for a myriad of widths and sizes. Many people are confused by the fact that they are manufactured in meters and not feet. America is the only large economy in the world that has not adopted the metric system. When converting meters to feet, one usually finds a tent that directly translates into an odd confusion of feet and inches. For example, a standard 30-meter wide clear span measures 98 feet, 5 inches, although it is known as a 100 feet wide within the industry.
When clear span fabric structures are discussed, the width of the tent structure is listed first, followed by the length. For example, 20 meters (wide) by 30 meters (long) is expressed in writing as a 20m x 30m (or verbally as 20 meters by 30 meters). Clear spans are manufactured and rented in the following widths (feet are approximate): 3 meters (10 feet), 6 meters (20 feet), 9 meters (30 feet), 12 meters (40 feet), 15 meters (50 feet), 20 meters (66 feet), 25 meters (82 feet), 30 meters (100 feet), 35 meters (114 feet), 40 meters (132 feet) and 50 meters (164 feet). The length increments of these tents are typically 3 meters (10 feet) for smaller clear spans up to 12 meters wide. For clear span tents 15 meters-wide or wider, they typically extend in 5-meter (16 feet, 4 inches) lengths. For example, 20-meters wide by 30-meters long tent can be extended in length to 35m, 40m, 45m, 50m, etc. Custom widths and lengths are not unusual, and a few rental companies have the ability to custom manufacture both the frame and fabrics to any size needed.
Clear span rental tents were a staple of the tent rental market in Europe before making their way “across the pond” and into the United States. For decades after WWII, some German, and later other European tent manufacturers, sold and rented what is generically termed a “clear span tent” throughout Europe. In 1981, the first container of clear span tents landed on the shores of the United States, destined for a nationwide tent rental company, American Pavilion. At first the U.S. market did not know what to make of these “metal” tents. Many called them a fad or a niche product, but because of all of the previously mentioned features, clear span tents have increased from less than 20,000 square feet in the United States’ market the first year, to a current inventory well exceeding 10 million square feet.
Hocker (sometimes spelled Hoecker) was the first clear span tent company to actively market and sell clear spans in the U.S. beginning in the early 1980s. They were quite successful due to their first move advantage and quality German engineering and manufacturing. Losberger, a large German manufacturer of clear spans, entered the American market in the 1990s with a quality German engineered and manufactured product. Both companies still manufacture and sell clear span tents to a network of U.S. tent rental companies and have been joined by more than a dozen competitors based around the world.
While clear spans come in both “straight rafter” with an 18-degree pitch to curved rafters, they all work on the same principle. They are all manufactured with an aluminum and steel framework and covered with a strong reinforced vinyl that can last for years and withstand incredible pressures. Once the aluminum frame is assembled and raised, the roof panels can be installed by pulling the top panels through grooves in the aluminum frame. This system aids in both installation and weather resistance. Typically, the sides of the tent open from the center of each 5-meter section and can be opened or closed quickly if inclement weather approaches. Hard sidewalls manufactured from molded plastic and other specialty materials may be installed for increased weather protection. Single or double entry glass or fabric doors can also be fitted for personnel ingress and egress, along with tall overhead rolling garage doors for the entry of semi-trucks and heavy equipment. These doors can be manually or electrically operated.
Clear span tent accessories for clear span tents are almost limitless. Floors (wood, carpet, stained planks, polymer plastics, just to name a few) along with glass entry doors, general and theatre lighting, HVAC, generators, power distribution, ceiling liners to hide the roof rafters, clear vinyl top panels, glass walls for greater outdoor visibility, and much more are available. While full-service clear span tent renters are limited in number, they should be able to provide most or all of the rental items listed above.
All clear span tents are supported around their perimeter with legs, also known as uprights, that vary in height. There has been a trend over time for clients to request taller uprights due to the fact that the higher the upright, the higher the roof, which increases the volume of the tent. The original clear spans came standard with a 2.4-meter (7 feet, 10.5 inches) upright height. That increased to 3 meters (9 feet, 10 inches) about a decade ago and is now the most popular upright height for mid-sized clear spans, those in the 15-25 meter width. Larger clear spans, starting at 30-meters wide are standard on a 4-meter (13 feet, 1 inch) upright height although 5 meter (16 feet, 5 inches) has entered the rental market over the past few years. As stated earlier, raising the upright height increases the peak height and internal volume, but it also increases the purchase and rental cost slightly. More importantly, it increases the amount of wind loading on the clear span. As side height increases arithmetically, wind pressures on the tent increase geometrically so a relatively small increase in side height can lower the wind rating (the amount and duration of wind gusts) for which a clear span is rated.
All legitimately manufactured clear span tents have been engineered to meet United States building codes as well as the more stringent DIN standards required in Germany and parts of Europe. Some code officials require both general engineering stamped by a professional engineer (P.E.) and also engineering stamped by a P.E. licensed to work in a particular state. Vinyl fabric covers the roof, sides, and ends of most clear span tents. Most of this fabric is manufactured in either Europe or the United States, and all states require that these fabrics meet stringent fire codes with the California Fire Code, one of the most stringent. Washing, sun exposure, and weather will not reduce the inherent flame resistance in these fabrics.
There are two main types of vinyl fabrics used in clear span tents. The first is a laminated vinyl material that has been on the market for over 40 years and has proven its capability many times. A laminated fabric is like a sandwich; there is an inner layer of mesh material (typically polyester or nylon) covered with a layer of solid vinyl on both top and bottom. These layers are then formed into a single piece with heat, pressure, or both. The other type of clear span fabric is a coated fabric that has become much more popular within the last 15 years. It also has a mesh in the center for strength, but the mesh is solid and covered top to bottom with liquid vinyl that hardens into a pliable material. The solid mesh is extremely strong and reduces pinholes (tiny holes) in the fabric that occur when washing or stepping on the material. Clear span tents can also be insulated, which is beneficial for long-term rentals. Most clear span tents are installed for a month or less and often for only a few days. One of the great attributes of clear span tents is their ability to stand for months and years with little to no maintenance. It is not unusual for a clear span to be installed for a year or more with no maintenance required.
The material on the rental market is manufactured in two main types of opaqueness: blackout and transparent. Blackout is the predominant fabric and it blocks 100% of the sun. This type of fabric helps keep the tent cooler and does not show any mildew. I know mildew sounds unappealing, but it does not compromise the material in any way. Transparent material allows most of the light to enter the tent during the day but also creates a hotter tent.
Both of these materials are inherently waterproof, but because roof panels are 5-meters wide, and no material is manufactured in that width, the fabric must be sealed together into a single piece. The only way to form a single piece that is water-proof is by using a high-frequency welder or HF welder. Contrary to its name, no flames or heat are used to form a “weld” rather, high-frequency radio waves are used to rearrange the molecules and form multiple pieces of material into one single piece that is as strong or stronger than a single piece of material. Heat is produced during this process in accordance with the first law of thermodynamics and is as complicated as a clear span tent will ever get.
The geographical reach of clear spans in the United States has extended beyond the original purchases made by American Pavilion 35 years ago. One may find clear span tents throughout the country, although within this niche in the tent rental market, there are maybe a half dozen companies with the inventories, truck fleets, experienced installation crews and logistical ability to operate throughout the United States. Transportation becomes a relatively small cost the larger the tent, and transportation prices are typically spread across the entire rental, so searching for the best vendor does not always mean the closest vendor.
I have attempted to provide a broad range of information covering every aspect of clear span tents to aid both beginners as well as those acquainted with the clear span tent market. The above was written by a fourth generation tent rental company owner who has learned a fair amount about clear span fabric structures. I started with clear span tents in 1981, and have since installed hundreds of them. My company, American Pavilion, has rented thousands of clear span fabric structures, along with manufactured millions of square feet of clear span tent fabrics. I trust that I have given a readable and accurate description of clear span tents. American Pavilion was at the vanguard of the clear span tent rental market and over the past 30 years has built its inventory to over 500,000 square feet. We also manufacture and repair all of our own clear span fabrics, giving us an insight into the types of material and manufacturing best practices.
For more information about our Losberger clear span tents, contact us today.