Pages from 20190823_16320.79_OBrien Upper Envelope Preliminary DESIGN Report.pdf

O’BRIEN UPPER ENVELOPE PROJECT

Preliminary Design Narrative Report

August 23, 2019

2. EXISTING CONDITIONS

A. GENERAL

The Leo O’Brien Federal building was originally erected in the 1970’s. The building is structurally a steel frame with cast concrete flooring with a masonry and stone exterior with vertical strip windows on all sides.

B. ARCHITECTURAL EXISTING UPPER ENVELOPE CONDITIONS

There are three (3) distinct roof levels at the building and all are under consideration for removal and replacement. Roofs included in this project are: 1. The lower cooling tower roof (area; 2,251 sq. Ft); 2. The lower perimeter roof between the mechanical penthouse exterior wall and the lower parapet(area; 1,169

sq. Ft); 3. The upper main roof (area; 14,1652 sq. Ft ) including the raised roof over the elevator equipment room (area; 1,121sq. Ft)

EXISTING MECHANICAL & LOWER ROOF PLAN (above) FROM ORIGINAL 1975 DRAWINGS Areas in blue are locations of roof core samples

1) Lower Cooling Tower Roof: This roof is located on the 10th floor on the east side of the building, in a light well that holds the cooling tower. The main roof surface is comprised of stone pavers over a modified bitumen roofing membrane over 1” of tar over composite metal decking with a concrete topping. There is an 8-foot-tall heavy steel frame that supports an elevated cooling tower. The steel posts sit in pitch pockets.

At the doors to the mechanical room there are 12-inch-high ramps down in the mechanical room.

2) Lower Perimeter Roof: There is a 1’-8” wide strip of roofing that encircles the entire 10th floor between the exterior wall of the mechanical room and the old masonry parapet. This roof appears to function as a “gutter”. On the North, West and South sides there are two drains each. The roof drains located here have failed or are in disrepair. On the East side, the perimeter roof sheet drains under the metal screen wall onto the lower cooling tower roof. These perimeter roofs consist of a modified bituminous membrane with stone ballast broadcast onto the surface, with no pavers. The roof above overhangs this perimeter roof and fortunately prevents the accumulation of most rain / snow and other wind-blown debris.

10th Floor Perimeter Roof with standing water Failed roof drain within Perimeter Roof

3) Upper Main Roof: The roof shape is a square with a higher raised section roughly in the middle over the elevator machine room. The main roof structure slopes to six (6) roof drains and one (1) gutter. The raised elevator penthouse roof has two gutters.

a. The roof material is made up of 3” of insulation board over metal decking, surfaced with layers of modified bituminous membrane and stone ballast broadcast onto the surface.

b. Snow drifting is not a problem because this high roof is surrounded by low parapets.

c. The roof is accessed by a single roof ladder with security cage from the Lower Cooling Tower Roof.

The ladder is in good condition for reuse and only needs to be scraped, prepped and repainted.

d. There are 10-foot-high metal screens at the four corners with Verizon cell phone antennas. Verizon signal cables run across the roof on top of PVC blocks.

e. There are lightning rods and grounding cables adhered to the roof. Exhaust ducts and vent pipes penetrate the roof.

f. There are no guard rails around the roof.

EXISTING UPPER ROOF PLAN (above) FROM ORIGINAL 1975 DRAWINGS Areas in blue are locations of roof core samples

Upper elevator penthouse roof with lightning protection Vegetation and bitumen ‘bubbles’

One of three corner enclosures for Verizon antennae Active satellite dish #1 Active satellite dish #2

Verizon cabling on sleepers heading east Cabling on sleepers on ‘catwalk’ over the “pit” Existing operable roof drain

C. PLUMBING SYSTEM EXISTING CONDITIONS

1. Lower Cooling Tower Roof: The Lower Cooling Tower Roof, located on the penthouse level of the east side of the building, is served by two 3” round primary roof drains. The drains are located in the north and south halves of the roof and match the locations shown on the existing design drawing 9-P-10 (c. 1971). The observed size of the drains also matches the sizes shown on the existing design drawing. This section of the roof is cricketed to provide slope toward the drains. A small portion of the upper roof (approx. 720 sq.

ft.) located above the east wall of this roof, drains to the lower flat roof via a gutter and two 2” downspouts.

There is no secondary (emergency) drainage provided for this section of roof. As a result, if the roof drains overflow, water can drain into the penthouse mechanical room via the two roll up doors located on the north and south ends of this section of roof. Per the existing design drawings 9-P-8 and 9-P-13 (c. 1971), the two roof drains serving this roof connect to a combined sanitary and storm sewer piping system. The drains are trapped and vented in accordance with 2015 IPC section 1103.1. During a site visit for this project, it was observed that the drain serving the south portion of this roof appeared to be clogged or draining slowly as a shallow pool of water developed around the drain.

2. Lower Perimeter Roof: In addition to the lower mechanical roof described above, there is a small perimeter roof area, approximately 2 feet wide, that runs the full length of the north, south, and west sides of the building. Each side (north, south, west) is served by two 3” round primary roof drains, and the locations and sizes match what is shown on the existing design drawing 9-P-10 (c. 1971). The roof is cricketed to each drain to provide slope towards the drains. There is no secondary (emergency) drainage provided for this section of roof. During a site visit for the project, it was observed that the drains located on the south side were completely clogged with debris. These drains are also located above areas within the building where water penetration into the building is a known issue.

3. Upper Main Roof: The upper main roof, which makes up the remainder of the existing roof of the building, is served by six primary roof drains. Each of these drains, aside from the drain serving the east zone of the roof, has a diameter of 4”. The drain serving the east zone of the roof is a round, 3” drain (see upper roof zone map). There is a drain located in each zone of the roof and they match the locations shown on the existing design drawings 9-P-9 and 9-P-10 (c. 1971). The observed size of the drains also matches the sizes shown on the existing design drawings. Each zone of the roof is cricketed to provide slope toward the drain serving that particular zone. A small raised elevator penthouse (approx. 1118 sq. ft.) is located in the center of the building that drains to the Upper Roof via gutters and two 3” downspouts located on the north and south sides of the penthouse. Secondary drainage for this roof is provided by water spilling over the parapet wall. Water spilling over the parapet will drain to the ground on each side of the building.

4. Existing Roof Primary Drainage Analysis: An analysis of the existing roof drainage system was conducted to determine if the system is sized appropriately to accommodate a 100-year storm as required per the 2015 International Plumbing Code (IPC), section 1106.1. Per IPC section 1106.1, the rainfall rate for a 100-year storm in Albany, NY is approximately 2.5 inches per hour. A roof area take-off for each drain was completed using existing architectural design drawings indicating roof drain locations and roof cricketing locations. As noted in the existing conditions summary, the design drawings and installed roof drain locations coincide with one another. Based on the roof area take-offs for each drain, the existing rainwater leader pipe sizes were compared with calculated values per IPC table 1106.2.

5. It was determined from the analysis that all the existing roof drains are sized appropriately for both horizontal and vertical piping. Attached in Appendix B are the roof area take-off maps, and the existing floor plans showing rainwater piping and sizing. A riser diagram of the existing rainwater drainage system is shown on existing drawings 9-P-10 and 9-P-13 (c. 1971). A summary table is provided showing all the existing roof drains, the total roof and wall areas each drain serves, the rainfall rate in gallons per minute each drain serves, and the associated code required vertical and horizontal piping sizes (at various pipe slopes) as required per IPC table 1106.2. All of the existing rainwater piping has adequate capacity in the vertical portions and in the horizontal portions with a minimum slope of 1/8” per foot. The existing design drawings indicate that all horizontal rainwater piping is sloped at a minimum of 1/8” per foot.

Clogged roof drain on lower mech. Roof. Clogged roof drains on Penthouse level perimeter roof.

D. HVAC SYSTEM EXISTING CONDITIONS

1. Lower Cooling Tower Roof: On the lower roof there are two cooling towers. The smaller cooling tower is

15’-6” x 7’-2” mounted on 2’ high supports. The larger cooling tower is 18’-0” x 18’-0” mounted on 8’ high supports. The cooling towers condensate drains are piped to existing roof drains. There are two (2) 2 ½” vent pipes with 4 ¼” x 4 ¼” curbs located near each of the roof drains. Along the west wall there are two

(2) 3 ½” vent pipes with 10” x 10” curbs.

Cooling Tower Condensate piping and 2 ½” vent pipe. (typical 2) 3 ½” vent piping (typical 2)

2. Upper Main Roof: In the raised center area of the upper roof there are four (4) exhaust duct penetrations.

There are two (2) dome type exhausts with 42 ½” x 42 ½” curb. There are two gooseneck exhaust ducts one 29” x 29” duct with a 34” x 34” curb and one 30” x 30” duct with a 40” x 40” curb. The ductwork and curbs are all in good condition. On the south end there are six (6) 14” boiler vents and one (1) 7” water heater vent coming up through the roof from the mechanical space below. Near the southeast corner are two (2) 50”x32” exhaust gooseneck ducts with 56”x38” curbs.

Four exhausts on the raised upper roof. Two exhaust ducts near southeast corner.

Six boiler vent pipes. Domestic water heater vent pipe.

E. ELECTRICAL EXISTING CONDITIONS

1. Lower Cooling Tower Roof: The lower cooling tower roof houses a few electrical panels and switches, most of which are associated with the HVAC system. Included in this electrical equipment is one (1) 400A, 480V Panelboard M1, one (1) junction box connected to Panelboard M1, two (2) 100A, 600V disconnect switches (one for each cooling tower), and one (1) 400A, 600V disconnect switch.

3. Upper Main Roof: The upper main roof serves as a mounting location for three Verizon Wireless antennas and two satellite dishes. The cables that provide power and communications to the antennas are protected by a rooftop kit consisting of PVC sleepers and a metal cover.

There are instances where the PVC sleepers have been damaged. The metal cover is installed such that it is raised above the PVC sleepers and is supported by the bracket.

Typically, this cover would be sized such that it is resting on the

PVC sleepers. With the exception of a few broken sleepers, this system is in good condition. The communications cables to the two satellite dishes are strung unprotected over the surface of the roof and down to the lower mechanical roof. These cables contain no marking indicating that they are listed for outdoor with exposure to sun and wet conditions.

4. The upper main roof also contains the building’s lightning protection equipment, which consists of 24 air terminals around the perimeter of the roof as well as three (3) air terminals on the surface of the roof and eight (8) air terminals on the raised roof section. The existing lightning protection does not protect all of the roof-mounted equipment. There are numerous HVAC vents that are taller than the air terminals and are therefore unprotected by the lightning protection system. The Verizon wireless antennas are also taller than the air-terminals and are unprotected by the lightning protection system. The air terminals located on the roof surface and on the raised roof section are mounted to small concrete pads which are not attached to the roof and could therefore be easily moved.

5. The physical location of these air terminals is critical to the proper operation of the entire lightning protection system. The 2017 NFPA 780 standard (Section 4.6.2.2.1(2)) requires that the air terminal be permanently and rigidly connected to the structure. These air terminals violate this requirement.

Panel M1 and Junction Box. Cooling Tower Switches

6. The 2017 NFPA 780 requires that the maximum spacing of air terminals around the perimeter of a building be 20 feet. This can be increased to 25 feet if the air terminal is a minimum of 2 feet or more above the object to be protected. The existing system does not meet this requirement in all locations. There is one air terminal connection point on the south side of the building where the air terminal is missing, which drastically increases the separation distance between air terminals. Finally, the 2017 NFPA 780 requires that the maximum spacing between air terminals on a flat roof be 50 feet (Figure 4.7.5.1(a)). The requirement is not met in the existing system. As a result, the existing lighting protection system does not adequately protect the building nor does it adequately protect the equipment mounted on the roof.

F. HAZARDOUS MATERIALS EXISTING CONDITIONS

1. Suspect material was sampled for both asbestos-containing materials (ACM) and lead-based paint (LBP) in multiple locations.

2. Black tar Chrysolite ACM was found at the time of the sampling, but only at the existing lightning protection grounding wire system attached to the existing roof system. This will need to be abated prior to roof demolition activities. The black tar “Pucks” that that adhere the lighting ground cable onto the penthouse and upper roof is an ACM.

3. The bottom layer of bituminous roofing membrane contained less than 1% ACM and in not considered a hazard at this time by the EPA. The modified bitumen material along the wall under the metal flashing on the lower roof contains less than 1 percent asbestos. For that material some OSHA requirements must be met (see report).

4. Painted surfaces contained less than 1% LBP and in not considered a hazard at this time by the EPA.

5. The report for the asbestos sampling is included in Appendix A.

Damaged Cable Supports

Improper Mounting of Air Terminal Missing Air Terminal