Category Archives: Products
As architects continue to imagine and design complex projects; it is becoming increasingly common that fall arrest and tie-back equipment are located on terraces of buildings.
As the condominium market is still as competitive as ever; builders and developers are coming up with special features and incentives to lure buyers. Items like barbecues, bars, built in kitchens, gardens, lounges, hot tubs, patio furniture, and even pools are frequently being included on terraces of buildings. While these are great selling features for buyers, they do create complications when designing window washing and fall protection systems.
These condominiums are so lucrative that every detail is considered. Therefore, as much of the buildings equipment is hidden as possible in common areas and private terraces (to not disrupt the aesthetics). This usually means on terraces that our equipment is recessed under some sort of removable paver stones. This regularly causes two major problems:
1) the paver stones over the recessed equipment are not actually removable
2) items are placed over top the recessed equipment
If it is planned accordingly there is a simple solution for problem “1)” as there are covers and inserts that can be manufactured and installed in paver stones that allow for them to be (rather easily) removed whenever recessed equipment (underneath them) require access.
If the design of the window washing and fall protection system is provided to the architect then the architect can review to ensure there are no disruptions.
What should the architect review?
1) They should ensure that no items (the special feature and incentives mentioned above or any others) are placed over top the recessed equipment.
2) They should confirm items that are in line with the point of suspension (perpendicular from the parapet to the equipment) will not interfere with the rigging lines.
This is where problem “2)” can become complicated. The architect and equipment manufacturer have communicated and reviewed all of the areas but then a tenant installs a deck and built in kitchen on their terrace (usually without contacting the condominium corporation). This makes accessing the recessed equipment nearly impossible which may mean a drop of windows cannot be washed or a section of the building façade cannot be maintained.
While usually a worker can move some items like small barbecues or potted plants, some items like large barbecues or large planter boxes simply cannot be moved. A worker in some cases may not even want to move anything because they are concerned about damaging the property.
It must be stressed to tenants the importance of communicating any additions and modifications to their terrace that they are making. The tenant should notify the condominium corporation and then the condominium corporation should contact the window washing and fall protection system manufacturer. Also, the condominium corporation should notify tenants when the equipment is going to be inspected or used so that the tenant can remove any items that are over the recessed equipment.
I often hear people referring to window washing systems as davit systems. While this certainly is true it is not the only way to complete window washing (see The Roof Anchor and Roof Anchors Explained for more). So what exactly are davits, davit arms, davit bases, and davit systems then?
Davit Arm Assemblies
Davit arms are commonly used to rig over non-structural parapets, decorative cornices, and glass balcony guardrails. These arms act as the primary suspension points usually for swingstages, but are also used for supporting single man cages and bosun’s chairs. Comprised of a mast (the vertical piece) and boom (the horizontal piece), davit arms are secured to the structure using bases. These bases vary to suit the roof or wall construction.
The main distinction in davit systems is whether or not the system is designed to be ground rigged or roof rigged. In a ground rigged scenario, each successive “drop” is done by picking up the platform from ground level, raising it to roof level, then back to the ground level. At ground level the platform is then moved to the next “drop” location.
In a roof rigged scenario, the mast on the davit arm is tall enough to allow it to pick the platform up from ground level, and hoist it onto the roof. The stage is then relocated on the roof level to align with each “drop” location.
- Davit arms are typically portable and are relocated to new bases for every drop.
- They can be broken down into segments for ease of carrying.
- Mast and boom size vary depending on building requirements.
- At times, arms that are very large or are required in difficult to access areas, are recommended or necessary to be permanently left in place for facade access. Also referred to as, “dedicated arms”.
There are many different types of equipment that are installed for window washing, suspended maintenance, and fall protection. They can include (but are not limited to):
- roof anchors,
- wall anchors,
- soffit anchors,
- rigging sleeves,
- horizontal trolley’s,
- gantry’s and
- roof cars.
With all the customized equipment out there – nine times out of ten it is a simple roof anchor that gets the job done!
Different companies (around the globe) use different styles of roof anchors that are each unique in their own way. A vertical steel pier anchor is the most common and are all pretty much the same. It is usually the actual tie-off (or anchorage point) that varies. Some companies utilize a swivel head U-bar that actually points horizontal (perpendicular) to the pier and can swivel while others have fixed “U-bars” or “eyelets”. These point vertical such as in the picture shown below. The material’s used from pier, U-bar, and hardware can vary in material from galvanized to stainless steel (depending on the project specifications) although stainless steel piers are not used very often due to cost.
These (steel pier) anchors can be installed to accommodate three different styles of systems: window washing, suspended maintenance, and fall protection.
Window washers can utilize anchor points to suspend themselves adjacent to the building facade to perform window washing operations. This is commonly done on a bosun’s chair but can also be performed on swing stages as well.
Companies performing facade maintenance such as brick restoration, window caulking, or balcony repair can utilize anchor points to suspend the platform (swing stage) that they work from.
Workers can utilize either individual, localized anchor points or a horizontal lifeline cable system to prevent them from falling (travel restraint) or save them from hitting the ground (fall arrest) in the event they do fall.
Often the simplest approach is the best one and window washing, suspended maintenance, and fall protection systems are no exception.
Pro-Bel was recently faced with the problem of installing a rigging sleeve on an existing building where we had no access to the ceiling below the roof.
The interior atrium of the building could not be cleaned (or maintained) because there was no lift/platform that would reach the height required (and there was no other access point to install any other equipment). The biggest problem though was that there was no access inside the ceiling and between the drywall and the roof there was a ten foot gap (which again complicated things even more).
What we did was add a large twelve foot extension bit to a drill and then (once we opened up the roof beside an I-beam) lowered the extended drill ten feet and drilled through the drywall below (to create a circular hole).
Once that was completed we installed the pier of the rigging sleeve by wrapping its base plate around the I-beam and then offsetting the pier.
Once the pier was installed we lowered a cable through it and the drywall hole and eventually all of the way to the ground floor. Once the cable was hung from the roof to the ground we were able to thread the cable through a PVC tube insert. The insert had a cap on the bottom which would give it a nice looking finish with the ceiling. We had to find a way to attach the cable to the insert prior to lifting it to the ceiling though so we secured an anchor to the end of the cable.
We then began to hoist the insert (along with the cap and anchor) up to the ceiling.
The insert eventually entered the pier and then screws were inserted into the side of each to secure it into place.
The rigging sleeve was then finished (like any other rigging sleeve) with a cap on top of the pier and the roofing around it was patched to a watertight condition.
This is the first time that we have ever completed an installation under these circumstances and it was an enormous success. There really is a solution to every problem!
We are often asked to provide our equipment on buildings with a standing seam roof. In the past this request would make even our most knowledgeable designers cringe but alas we have engineered a solution.
What is a Standing Seam Roof?
A standing seam roof consists of a series of sheet metal panels that are connected “above” the panels (creating a “standing seam”) in a manner that does not penetrate them.
These are some examples of connections:
Pro-Bel is an official distributor of S-5!® clamps (as seen in the picture below) which connect the panels by tightening the seams together. You can learn more about this product from their website (http://www.s-5.com/home/index.cfm) and by following them on Twitter @S5_TheRightWay.
The big obstacle with our equipment being on a standing seam roof is that the panels will not support the applied load/force that our equipment is engineered to accept.
CAN/CSA-Z271, Section 6.3.2 – “Strength Requirement” asks that all “anchoring systems shall be designed to resist a force” of five thousand (5,000) pounds. This load/force is indirectly applied to the structure of the roof as well which is where the problem arises.
The Ridge Cap Flashing
Usually with a sloped roof there is a gap at the peak of it between the panels. This is usually covered by a ridge cap flashing which actually does penetrate the flashing and panel (in a strategic way). As seen in the picture below, Z bar connection penetrates the flashing and connects it to the panel. As long as the penetration is “above” and “away” from the envelope (the area inside the flashing) there is no concern for water damage. If the Z bar is installed incorrectly (as shown on the right side of the picture below) then water could potentially enter the envelope and travel toward the unprotected roof material and structure.
The flashing will run along the peak of a sloped roof with a large amount of connections (nails or screws) running along each side of it like so:
Our Engineers agreed that the connections make the flashing the strongest component of a standing seam roof and thus the ideal location to install a piece of our equipment to.
What we did was design a large galvanized rectangular plate with ninety degree angle pieces welded to it (the plate). Our standard stainless steel U-bar is centred on the plate and the angles would be screwed into the flashing (standing seam where the Z bar would be) instead of penetrating the envelope or panel.
We hope to build upon this application as this solution will revolutionize fall protection systems on a standing seam roof.
Every type of roof structure presents its own unique challenges in new construction for companies who supply and install permanent equipment on them. With structural steel its reinforcing, with concrete it can be missing a pour. Hollow core precast can be looked at as one of the most challenging roof construction types for the installation of window washing, suspended maintenance and fall protection systems.
The main issue with precast lies with the fact that there usually is no drop ceiling underneath. It is quite often stucco and even plaster which means bolting through the structure would require leaving a backplate exposed to view at the underside of the precast. Not only is this not aesthetically pleasing, it also presents a potential danger to the workers who use the roof anchors as the base securement of the anchors is exposed and could potentially be tampered with. This provides us with two options: cracking open the cores and grouting the anchor in or having the precast manufacturer embed plates.
Grouting A Roof Anchor Into Hollow Core Precast
This option requires two cores to be broken open and embed plates at bottom of the bolts to be cast in with rebar and grouting. This prevents from having to bolt through the structure but is very labour intensive and thus costly. Ideally in new construction the roof anchor company would supply only this anchor and leave it up to the general contractor to break open the cores and grout the anchor in. Grouting in hollow core is quite common.
Having The Precast Manufacturer Embed A Plate
This option although the most cost effective when you cannot bolt through, is unfortunately very impractical and rarely used. An embed plate is sent to the precast manufacturer along with an engineered stamped layout showing the location of the roof anchors on the roof plan. The precast manufacturer then embeds this plate in to the hollow core structure at the appropriate locations. The roof anchor manufacturer goes to the site afterwards and welds the pier and U-bar in place. The problem with this approach is that the precast manufacturer will usually not want to take responsibility for casting the embeds in.
At the end of the day bolting through is the best way to go but when you cannot here are a few options for you to consider.
Roof Anchors are the most common piece in the permanent window washing equipment industry. This article will help you better understand what a roof anchor is and why they are so popular.
A roof anchor at first glance is a very simple product, a basic post with a u-bar attached to the top. Looks can be deceiving and when it comes to roof anchors there is much more than meets the eye. Several factors need to be taken into consideration when designing and manufacturing a roof anchor. First we must know that the intent of the roof anchor is to protect the people who otherwise may be exposed to a fall. A typical Pro-Bel roof anchor is designed to meet a 1,000 lbs static load and a 5,000 lbs ultimate load. The static load is the allowance for a constant fixed load to be placed on the anchor. The ultimate load is a one time force in which the anchor is permitted to bend but may not fracture or detach. Some areas have regulations for roof anchors that are much stricter such as California.