RCB Elevator Consulting, LLC Elevator Shop Drawings & AutoCAD Drafting Elevator Consulting & Engineering November 22, 2006 Bill Doyle Tenderloin Neighborhood Development Corp. 201 Eddy St. San Francisco, CA 94102 Project:
Ritz Hotel, 216 Eddy St., San Francisco, CA
Subject:
Elevator Report
Dear Bill, Per your request, I have surveyed and prepared the following report regarding the single elevator at the Ritz Hotel, 216 Eddy Street, San Francisco, CA.
Elevator Quantity: Designation(s): State No: Original Manufacturer: Installation Date: OEM No.: Modernization Co.: Modernization Date: Modernization No.: Service Type: Drive Type: Weight Capacity: Speed: Machine Location: Stops & Openings: Rise: Door Type:
Existing Equipment Data One (1) #1 14455 Otis Elevator Company 1928 2135 Fischer Elevator Company 1984 216 Passenger Basement Winding Drum 1500 lbs. 175 fpm Adjacent @ Basement 6 Stops & Openings in Line Approximately 58’ Manual Swing Door
Equipment Description The existing conveyance system at the Ritz Hotel is known as an electric basement winding drum, swing door passenger elevator. According to the records of the State of California, DOSH, Elevator, Ride and Tramway Unit, the jurisdiction having authority (JHA), it was originally placed in operation in 1928. At that time the electrical service feeding the system was utility-provided 220 volts direct current (VDC), the control system would have been a very simple open magnetic relay controller directed by a human operator with a manual car switch. The elevator car would likely have been an all hardwood cab or possibly a metal grill cage type cab with a collapsible car gate, and with swing doors at the lobbies. The winding drum machine can be described as a device with a DC drive motor with rotating armature shaft in line with a worm gear, connected via a brake drum hub. The worm gear turns a ring gear on a common shaft carrying a rope drum. Two steel cables hitched to the car, extend up the hoistway to a rooftop sheave room, travel over sheaves and back down the hoistway alongside the car, wrap around the machine drum and then against a machine mounted deflector sheave, travel back up the hoistway to the sheave room, over another set of 2117 Bush Street San Francisco, CA 94115
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sheaves and back down the hoistway to one section of the counterweight. In addition to this main support cable loop, there is a second loop of two steel cables that are also hitched to the car, extend up the hoistway to a rooftop sheave room, travel over a sheave and back down to the second stage of the counterweight. This elevator has the original standard T-shaped 15 lb/ft steel car guiderails and 8 lb/ft steel counterweight guiderails as well as the original bracket connections to the building structure. (Many elevators of this vintage and earlier had hardwood guiderails in lieu of steel.) The overhead sheaves, which support the suspended elevator car and counterweight, are supported by steel beams. These sheave beams in turn rest on wood building beams over stud framing at the hoistway perimeter. Located in the overhead sheave room is the original Otis flyball nonswitched overspeed governor. The governor is driven by a steel cable connected to the original drum type wedge clamp progressive safety located under the car. Equipment Modernizations I could find no records or evidence of the equipment being altered from the date of installation until the 1950s. The elevator was modernized in the 1950s to change the control operation to automatic pushbutton, replacing the human elevator operator. This would have involved a complete replacement of the electrical control system and the replacement of the manual car switch in the car with a pushbutton actuated car operating panel fixture. New hall call fixtures would have been added as well. Electromechanical interlocks would have been added to the lobby entrances, either to the existing door or possibly new doors and entrances were installed. A state report suggests the system may have been further modernized in the 1970s as is shows a different brand of interlock installed than shown on an earlier report. However, there is little additional information provided. A major alteration occurred in 1984 when Fischer Elevator Company installed a new G.A.L. brand control system. The elevator was converted from being powered by utility-provided 220 VDC to new incoming 208 volts alternating current (VAC). This required the installation of a motor-generator (MG) set that functions to convert the incoming AC power to DC power as required by the winding drum machine drive motor. A new electrical car selector and leveling system were installed. Also included in this modernization are a complete new cab, new car and hall operating fixtures, a seismic switch, automatic door operator, new swing door entrances, new interlocks, wiring, etc. This was the last major upgrade to the elevator system. The building had undergone extensive upgrades, including seismic retrofit, but nothing more, it would appear, was done to the elevator system at that time. Winding Drum Machine History The winding drum was a very prevalent elevator system installed from the 1880s through the 1930s. However, they were no longer permitted by the elevator code to be installed in California and most of the country beginning in the late 1940s and the 1950s. They had fallen out of favor for a number of reasons, chief among them the potential for system damage and life safety concerns should the drive machine continue to run after the car has reached its terminus at either end of its travel. There are required safety devices, both machine and hoistway switches, that are to shut down the elevator should the car continue to run past the terminal landings. However, if the control system malfunctions and these safety devices fail, and the car over-travels, the winding drum type system will likely fail catastrophically. The potential is to pull the car or counterweight into the overhead until something breaks. This is, in my understanding, the principle reason why the winding drum type elevator system gave way to the more modern traction elevator system. With a traction elevator, the ropes simply loose traction (slip) in the event the machine continues to run with the car at the terminus. Until 1998 the elevator code in California, CCR Title 8, had prohibited the major alteration (modernization) of winding drum elevators. The state DOSH senior safety engineers had made it clear that not only did they not want these systems altered; they really wanted these antiquated systems phased out and replaced with a more modern system. The thought was that if winding drums were not allowed to be upgraded and had to remain original, they would over time no longer be operationally viable and owners would have no choice but to tear them out and install a new system. There have been a number of attempts by the JHA over the past 30 years to mandate, through regulations, to force the replacement of winding drum elevators. The California Standards 2117 Bush Street San Francisco, CA 94115
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Board has even prepared tentative language for such regulations. The most recent attempt, only a few years ago, got to the stage of legal review and it was determined by the state’s legal advisors that such a mandate would constitute an unreasonable hardship on building owners. A provision was added to the proposed language to allow the winding drum to remain if its operational and structural viability was certified by a California licensed engineer. We looking into the possibility of providing such certification and concluded that such a blanket certification could not be responsibly provided. The principle reason is the inability to certify the machine’s anchorage, which could not realistically be accomplished without destructive measures. Also, certifying the structural machine castings would as well likely require destructive metallurgy testing. Further, it would be unprecedented to provide such a blanket certification, tantamount to accepting liability for the machine in perpetuity. It would be reasonable to ask, what are the failure rates for winding drum machine elevator systems? Have there been numbers of failures resulting in personal injury or loss of life? Are the systems inherently unsafe? I cannot answer these questions as I don’t have the statistics. It is my understanding that there have been injuries and fatalities caused by failed winding drum elevators. I have seen operating winding drum elevator machines with structural gearbox casting fractures and with wear so extensive as to be a safety concern. It is the general consensus of industry professionals that these antiquated, obsolete “dinosaurs” should be phase out of use and replaced with modern, proven systems. However, the elevator code currently in effect in California since 1998 does allow winding drum elevators to be retained and modernized. Companies are refurbishing them with new motors, solid state controllers, selectors, leveling systems, cabs, fixtures, power operated entrances, etc. It is the author’s opinion that, with rare exception, winding drum machines should not be retained in a system modernization. After 80 or more years of continuous operation, they have served their useful lives and it is generally time for them to be replaced. Elevator Condition & Deficiencies The general condition of the winding drum elevator at this facility is best described as poor. There is extensive, pervasive wear shown throughout the system, as would be expected due to its age. There is considerable play in the major bearings and seals of the original Otis flat-head motor, the worm & thrust bearings, and in the drum bearings. The bearings in the overhead sheaves in particular show massive wear and settling in their pillow blocks. All of these bearings are early poured-babbit type, which originally contained asbestos for longer wear ability. To replace the bearings is to rig up and re-pour the babbit in place – a largely lost art. (Modern machines and sheaves use roller or ball bearings, which are relatively easy to replace.)
original winding drum machine
overhead sheaves
babbit bearings
From reading the Machine Room Log, there is evidence of considerable door operation failure issues. The door contacts are a chronic problem, typical of older swing door systems. The keeper located on the upper outside 2117 Bush Street San Francisco, CA 94115
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corner of the swing doors has to make up electrically and mechanically with the interlock device. With any normal wear and sagging of the door panels, these connecting parts come out of alignment. The doors close via hydraulic closers that vary in force, often either not closing sufficiently or slamming, further aggravating the alignment issue. Swing doors are more inclined to be obstructed by debris, resulting in system shutdown.
entrance at street level
basement entrance & machine room
entrance at typical floor
The Log also shows considerable controller malfunction including blown fuses, coil failures, missing selector signals sending the car into the pit and overhead limits, etc. Keeping the MG compounding stable is always an issue with type of system. The mechanical selector and leveling system is an antiquated, chain driven, electrical/mechanical tree system which functions to mimic the rise of the building in miniature. These are notoriously inaccurate, resulting in uneven leveling which can cause tripping hazards. Some parts are still available for the 22 year old control system but many are obsolete, making repair difficult. The combination of the archaic controls, use of a MG power conversion, and the heavy DC motor make the system very inefficient in terms of power consumption. The MG appears to run continuously, even when the elevator is not called for extended periods, resulting in energy waste, equipment wear, dirty carbon dust proliferation, and the irritation of the constant high-pitched noise it produces.
G.A.L. relay controller 2117 Bush Street San Francisco, CA 94115
motor-generator in wood enclosure
selector leveling tree
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The original fly-ball governor is noisy, with its open greased gearing and babbit bearings. It is somewhat hazardous to work around due to the exposed, rotating members (as are the exposed, unguarded sheaves). The governor does not have an overspeed switch, as modern governors do by code, which shut down the elevator system electrically at 90% of the mechanical tripping speed. However, the existing original overspeed drum activated wedge clamp safety is in good shape and this type of safety has proven to remain serviceable. They get virtually no wear as they are rarely operated.
flyball non-switched governor
drum wedge clamp safety
The existing steel bracketing connecting one of the car and both of the counterweight guiderail stacks are structurally inadequate. The elevator and counterweight are prone to becoming displaced outside their guiderails in the event of a moderate earthquake. The counterweight is a frameless sash weight type, prone to failure in a seismic event. The winding drum machine anchorage is not proven to withstand anticipated seismic forces. There are no counterweight displacement sensors. The existing seismic switch is a single axis device, in lieu of the dual-axis now required. There are no elevator rope (cable) displacement guards. There is no car emergency exit latch with lockset or contact switch, as is now required.
right side car & counterweight guiderails & brackets
single-axis seismic switch at controller base
The elevator car, replaced in an earlier modernization, is undersized from the original cab. Although the platform measures 55.5” wide by 56” front to back, the existing car inside only measures 48.75” wide by 45.75” from the front return to rear wall. This clear car inside does not make even the minimum clear car requirement of 48” square. The existing two-speed, power operated car door entrance measures 32.75” wide by 80” high. The existing non-ADA compliant car operating panel is located on the car side wall near the entrance strike side.
2117 Bush Street San Francisco, CA 94115
phone: 415-819-5744 fax: 415-354-3454 e-mail:
[email protected] web: bl k
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There is a car riding lantern centered on the car rear wall. The car does have a compliant handrail. The hall stations are of legal height but lack the required fire existing instructions.
rear & right side of car
front left side of car
The existing building elements that house the elevator system are not in adequate or serviceable condition. The machine room and rooftop sheave room are not fire rated assemblies. The machine room walls (except the one concrete exterior wall) and ceiling are constructed of exposed open wood boards on the exterior and galvanized sheet metal interior. The machine room and sheave room access doors are clearly not fire rated and do not include proper locksets or closers. There is inadequate lighting and no GFCI service outlets in the machine room, sheave room or pit. The hoistway walls have numerous breaches in the wire mesh and plaster fireproofing. The pit floor slab is a jumble of uneven concrete and grease. The skylight over the sheave room is open to the elements at the peak. There are smoke detectors at the elevator floor entrances and in the machine room. However, there doesn’t appear to be sprinklers in the machine room, overhead sheave room or hoistway. If these are added, heat detectors and shunt trip power would be required.
machine room entrance
machine room construction
overhead sheave room
Option Analysis & Recommendations New Full Size Overhead Traction Passenger Elevator: In an ideal world, the best solution would be to install a complete new, full sized, standard dimensioned 2500 lbs. or greater capacity, ADA compliant, ambulance stretcher compliant, overhead traction passenger elevator. This new elevator would be installed either largely in the space of the existing winding drum elevator, but by expanding the existing hoistway in both width and depth, 2117 Bush Street San Francisco, CA 94115
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or in a completely new hoistway from space taken from other areas of the facility. Either option would not seem tenable due to the extensive building reconstruction that would be required. Expanding the existing hoistway would require cutting into adjoining spaces, including stairwells and tenant space, with the attendant structural work required to re-support all of the floors, etc. Additionally, a new machine room would have to be built on the roof, new electrical utilities provided, and a host of related building improvements. The option of building a new elevator in a new location would have similar issues and would likely impact existing usable space even more. The option of installing a new, full sized elevator is more suitable for projects where the original structure is gutted and reconfigured. It is not viable for a finished and occupied facility such as this. The cost and disruption would be too extensive. Modernize the Existing Winding Drum System: Much of my previous report speaks to this issue, suggesting that modernizing the existing winding drum elevator is not advisable. Though it is currently an option allowed by the code, should the JHA succeed in their intentions, this could change soon enough to have made the investment a poor one. There are many engineering uncertainties in retaining the old winding drum machine. The structural integrity of the machine itself, the metallurgy, the gearing strength, its anchorage, the integral overhead sheaves are all under suspicion – especially when considering seismic forces, which were never envisioned in the original equipment design. Also, a simple but fair question to ask is what should be the operational life of a major piece of equipment such as this, one that runs largely 7/24 and has for 80 years? In my assessment, the owners have done well to have gotten such long service and should retire this piece of equipment. Traditional In-Ground Hydraulic Elevator Replacement: Many of these early winding drum elevators have been torn out and replaced with a custom sized, traditional, single-jack, in-ground hydraulic elevator. There is some advantage to this approach in that no counterweight is required so that space can be recouped for a slightly larger car. This project has a fairly small counterweight footprint that is at the side of the car in front of the right hand car guiderail, so the potential increase in car size would be approximately three inches in width. The inground hydraulic elevator becomes less viable as an option for the rise of this facility of almost 60 feet. To make the piston structurally and seismically rigid with respect to buckling failure, it must be comparatively large and heavy. Consequentially, a large pump unit in motor size, pump output and volume of oil would be required. All hydraulic elevators are substantially less energy efficient than electric traction elevators, and one to suit this design would be especially inefficient. Hydraulic elevators are also not as durable as traction elevators. Another major drawback to the in-ground hydraulic option would be drilling a 65 foot hole in the ground below the pit floor. This area of the city is known for difficulty in sinking holes of any considerable depth, even when employing a powerful truck mounted rig. This job would require a portable drilling rig with far less ability to conquer the likely drilling obstacles. Whereas otherwise installing an in-ground holed elevator would be the least expensive elevator replacement, the drilling unknowns and likely extended costs would offset any potential savings. Another consideration is the future possibility for groundwater contamination should the buried hydraulic cylinder ever develop a leak. Although, secondary containment and monitoring have improved, the industry trend is away from buried cylinders for this reason. For all the reasons mentioned and more, I cannot recommend the replacement of the existing elevator with a traditional in-ground hydraulic elevator. Roped Hydraulic Elevator Replacement: The newest technology in the hydraulic elevator category is the roped hydraulic. Unlike the traditional, in-ground holed hydraulic, the roped hydraulic elevator uses two hydraulic jack assemblies that are located at the sides of the elevator car and rest on the pit floor. This does away with the problems of drilling the jack well hole and eliminates the potential of underground oil leaks. The car is suspended by ropes (steel cables) similar to a traction elevator except that the ropes dead end hitch to the jack assemblies, run up over sheaves attached to the top of the jack pistons and back down to the base of the car. As such, the car is ropes 1:2 – every inch the hydraulic pistons travel the car travels two inches. Because of this roping scheme, the roped hydraulic is better suited to the higher, nearly 60 foot rise. The disadvantage of employing a roped hydraulic passenger elevator replacement option for his project is that, for this rise, most manufacturers require 10” of space on each side of the car platform for sufficient room for the hydraulic cylinders and equipment. As the existing hoistway are fixed for structural reasons at 70” in width, this 2117 Bush Street San Francisco, CA 94115
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would provide for a platform width of only 50”. Using a thin walled cab design we could get an inside clear cab width of 48”, the absolute minimum allowable by code. However, we may have difficulty getting the 36” minimum clear entrance width due to insufficient opening refuge space caused by the effective shift in entrance towards the center. Design engineering would have to be performed to see if this problem can be resolved. Other disadvantages are that the roped hydraulic is still not as energy efficient as a new traction equipment. The motor horsepower is roughly double that for a geared traction configuration of the same elevator duties. Also, the roped hydro would be less durable, less robust for the heavy use that this single elevator sees in this active and fairly large facility. Further, changing the elevator type from an electric cable elevator to a hydraulic elevator is considered by the JHA as a “new installation” as opposed to an “alteration.” A new installation triggers a number of code requirements that an alteration does not. One example is the existing pit depth is acceptable for an alteration but would have to be deepened for a new installation. A roped hydraulic elevator replacement would be a viable option but less than ideal. With the additional, larger electrical service required to power it, the deeper pit, and other issues to be dealt with, there would be little savings realized by this option over the preferred option listed below. Winding Drum to Geared Traction Conversion Alteration: The best solution for this application is to convert the existing basement winding drum elevator to a modern basement geared traction passenger elevator. This plan would replace all of the obsolete, antiquated, non-complying, and unserviceable equipment with new, state of the art systems while retaining those elements of the existing elevator that are completely viable. Per the JHA, this constitutes an alteration to the existing elevator which relieves some code issues that are not serious life safety items and don’t affect quality of service. This option will yield the best quality elevator system functionally, will provide the greatest length of service, and the most energy efficiency. A reasonably brief description of the design and scope of work follows: The car speed would be 200 FPM (same as elevator originally) and with 1500 lbs. rated capacity. Replace the existing winding drum machine with a new modern geared traction hoist machine with a VVVF-AC low slip drive motor. Connect and anchor the new machine via an adapter plate to the existing retained winding drum machine bedplate, plus a structural shear plate with anchors into the concrete pit wall and base structure. Structural engineering will be requireed to certify the anchorage. Replace the overhead sheaves with modern sheaves for the roping scheme to match the new drive machine. This also requires structural engineering to certify the equipment connections and the load support capability of the structure. Retain and refurbish the existing car sling, platform and overspeed safeties. Provide a new overspeed governor with overspeed switch. Provide a new compliant frame-type steel counterweight. Provide new car and counterweight spring buffers. Structurally reinforce the existing car and counterweight guiderail stacks. Reinforce existing and provide new bracket connections to the structure as required. Design to current seismic criteria. Structural engineering is required. Provide a new complete cab assembly with entrance size of 36” wide by 84” high. The cab shall be of a fire rated thin wall custom design with side walls set within the existing car sling stiles to yield a clear car width of approximately 53” wide (less stile intrusion) by 48” from front return to rear wall. This constitutes an increase in usable car size of almost 15% over the existing car but is still within the 1500 lbs. capacity rating. Owner shall obtain a hardship exemption for this size of car. Provide all ADA and Title 24 accessibilities requirements (except for minimum size of car) including new car and hall operating fixtures, visual & audible indicators, Braille, etc. Provide special accessibilities requirements for undersized elevator cars as required by San Francisco’s Mayors Office on Disability (MOD) including car operating panels at both front & rear and a mirror at the rear wall. New power operated side-slide opening elevator entrances at the floor landings. Entrances shall be 36” wide by 84” high and shall be located into the building lobby space, outside the existing hoistway line so as not to decrease the usable hoistway space. This will require complete removal of the existing swing door entrances and elevator hoistway front walls from the floor to ceiling and side to side. 2117 Bush Street San Francisco, CA 94115
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Provide complete new solid state elevator control, selector and landing systems with all new wiring, switches, VVVF-AC motor drive, fire service, earthquake operation, independent service, etc. Provide attendant building re-work including: repair or replace fire rated enclosing and accessing of hoistway, machine room and overhead sheave room; enclosing the front walls into new entrances; machine room, pit & overhead sheave room lighting & convenience outlets; working platform in overhead sheave room; leveling the existing pit floor; possible upgrades to the building life safety systems including smoke & fire detection, sprinklers, heat detectors, shunt trip, etc.; smoke barriers at each landing via hold back doors or smoke curtains; as well as other sundry items.
The engineering work required to properly design and certify a winding drum to geared traction conversion as described in the above scope of work is quite extensive. Converting an antiquated winding drum system to a modern geared traction system is far more complex than installing a new elevator. Custom design layout shop drawings must be prepared in concert with proper structural engineering. Running clearances are tighter, accommodation of existing equipment and building structures are more involved and there are no existing or asbuilt plans to draw from. It would be advisable to conduct an onsite consultation with JHA to prove out the plan and obtain the JHA’s pre-approval of all code issues. Traditionally, the elevator engineering is the responsibility of the awarded elevator contractor. However, on these types of very complicated conversions, we have found that it works better to fully engineer the job in advance of bidding out the work. In this way, all competing contractors, from the GC, sub-trades and the elevator contractors, can use the fully engineered plans to more precisely estimate their scopes of work. The alternative is to bid the job with little more than a specification, which on these complex jobs either leads to contractor underestimating and demands for extras for supposed undefined or unforeseen work or it leads to gross padding of estimates to cover the inability to estimate with greater accuracy. Also, with the job pre-engineered, the elevator contractor can proceed immediately with purchasing and fabrication, speeding up the time line to construction after contractor award. The elevator conversion project (actually, any of the options described) would require obtaining building permits from the City and County of San Francisco. To my understanding, architectural support would be required to obtain such permits. I believe the City will require a submittal package beyond the extensive elevator design and structural engineering package referred to above, though that would be a part of it. They typically require an overall building floor plan, egress plan, ADA compliance certification, hardship application and, documentation as applicable, and other items. The owner should plan on the expense of retaining a licensed architect for these services. The cost for all work involved is difficult to estimate and would vary depending on the contractors chosen. Due to the substantial portion of the work to be performed by an elevator contractor and relatively minimal work required by other trades, I would recommend the owner contract with the elevator company directly, if possible, to save the general contractor markup on the elevator work. I would estimate the elevator portion of the work to be approximately $250,000 to $300,000 and the ancillary building work to total $75,000 to $150,000. These numbers could be substantially off depending on the economic climate at the time of bidding and the general interest in the project. You may wish to take a more conservative approach to budgeting and add to these numbers. You can view samples of winding drum to traction elevator conversions at my website: Cartwright Hotel, San Francisco http://www.blaska.com/Cartwright_Hotel.htm The Chew Building, san Francisco http://www.blaska.com/Chew_Bldg.htm and an article about winding drum to traction conversions at: http://www.blaska.com/winding_drum.htm I hope this report has helped illuminate your understanding of the elevator situation at the Ritz Hotel. Feel free to call if you have any questions or if I can be of service. Regards,
Richard C. Blaska Principal RCB Elevator Consulting, LLC 2117 Bush Street San Francisco, CA 94115
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