b'aged area. While not conclusive proof, the teststrate, but properly installed membranes have dramatically advances the argument beyondno trouble passing. the "yes-I-did," and "no-you-didn\'t." TheseAll the components are housed in a sturdy tests have kept contractors out ofHow aluminum box forto the roof for quick court.transport ever, as a caution to the imprudent, the oppo as~embly. The apparatus can then be moved site can also occur.from place to place on the roof without being As you can see, the ability to perform thesereassembled. tests not only can be profitable, but also canOn gravel surfaced roofs only the perimeter, enhance the image of the contractor as tech where the base of the dome must bear, must nologically advanced - a reputation that is, un be swept to remove the loose gravel and fortunately, not as common in our industry as itpoured with fresh asphalt to achieve a good should be.seal. On all roof surfaces a roll of duct tape "So," you say,"this seems like something Imay be required to help the gaskets on the might want to pursue. How do I go about it?"dome seal to the roof surface. It should be Funny you should ask.noted that some minor leakage is necessary for Midwest RCA possesses the technology,the device to work, as long as the force of the production and expertise to furnish the equip vacuum exceeds the leakage the dome works. ment to perform these tests. Here is a descrip After some practice the test is easy to perform tion ofequipment and how it works.and control. the The basic concept requires the assembly ofMidwest RCA is proud to have had a hand in a 5 feet-by- 5 feet dome placed overdeveloping this device and special thanks goes the roof covering; then, by means of a vacuum source,to Paul Morris and Ray Johnson, two Midwest negative pressure is applied to the membrane,RCA presidents who were instrumental in getcreating uplift, the same force caused by windting the technology developed and accepted by passing across the top of a surface at a higherboth ASTM and Factory Mutual. speed than that passing under it. Like the cur Midwest RCA, in its role as contractor advovature of the top surface of an airplane wing,cate, is pleased to offer this test equipment for the air must travel faster across the top to getboth sale or rent to its members, at a reduced to the same place as the slower air passing un rate, and to the general roofing public so that derneath - hence, uplift. It\'s the same force thatthis increasingly accepted procedure can bethe wind applied to a building roof and the upliftcome a quality part of the professional services dome apparatus duplicates it - a very convinc you provide. ing test.For details on the purchase or rental costs Nuts and bolts, how does the uplift domecontact Karleen Ballmer at the Midwest RCA work?The dome consists ofoffice in Lawrence. Kan. four identical sections or quadrants that are field assembled on the roof. There are two holes in the dome; one is attached to the vacuum source; the other is attached to a device called a water manometer that is used to measure the uplift force being applied to the roof covering. Basically, the manometer is a column ofthat, as it is water being slowly pulled down by the vacuum inside the dome, gives measurable readings of what is happening. The vacuum can be increased, decreased orby the use of a rheostabilized stat that controls the motor speed of the vacuum. A bar spanning the width of the dome, with a dial indicator attached, is placed inside the dome to measure the movement of the roof covering. The tolerances and modes of failure are described in the texts of the aforementioned standards, but suffice it to say that the results can be dramatic. This device can literally rip a poorly attached roof from the sub-MRFebruary 9611'