SAN FRANCISCO
HISTORIC PRESERVATION COMMISSION

 

Meeting Minutes

Commission Chambers Room 400,
1 Dr. Carlton B. Goodlett Place
San Francisco, CA 94102-4689

Wednesday, September 21, 2016
11:00 a.m.
Architectural Review Committe
Site Visit
 

COMMISSIONERS PRESENT:   Wolfram, Pearlman, Hyland
COMMISSIONERS ABSENT:     Hasz

THE MEETING WAS CALLED TO ORDER BY COMMISSIONER PEARLMAN AT 11:12 AM

STAFF IN ATTENDANCE:   Eiliesh Tuffy, Tim Frye - Historic Preservation Officer, Jonas P. Ionin – Commission Secretary

SPEAKER KEY:
+ indicates a speaker in support of an item;

• indicates a speaker in opposition to an item; and

= indicates a neutral speaker or a speaker who did not indicate support or opposition.

Hearing Materials are available at: Website: http://www.sfplanning.org Planning Department, 1650 Mission Street, 4th Floor, Suite 400 Planning Information Center, 1660 Mission Street, 1st Floor Voice recorded Agenda, only: (415) 558-6320 Commission Hearing Broadcasts: Live stream: http://www.sfgovtv.org Ordinances and Accessibility Hearing Procedures

 

1. 2016-007806COA                                         (E. TUFFY: (415) 575-9191)
THE GOLDEN TRIANGLE LIGHT STANDARDS – located curbside on various public right-of-ways generally bounded by Mason, Sutter and Market streets (District 3) - Request for Review and Comment by the Architectural Review Committee regarding the proposal to replace the existing cast iron cladding and light globes on approximately 189 historic light fixtures with cast fiberglass replacement fixtures, created from molds of the original design. The light standards are leased by the city to the Pacific Gas and Electric Company, who operate and maintain the fixtures as public utilities. Originally installed in 1918, the ornamental metal fixtures lined the streets of the historic downtown shopping district surrounding Union Square. The Golden Triangle Light Standards are designated as city Landmark #233 under Article 10 of the San Francisco Planning Code. The sites are located in the downtown commercial C-3-G (Downtown - General) and C-3-R (Downtown-Retail) Zoning Districts and an 80-130-F Height and Bulk District.
Preliminary Recommendation: Review and Comment

SPEAKER:

None

ACTION:

Reviewed and Commented Recommendation: The proposed project would result in a 100% loss the existing cast iron cladding, which is the predominant character-defining feature of the designated landmark. A project resulting in the complete loss of original historic fabric would call into question the validity of the Article 10 Landmark Designation. The Committee agreed with the department's recommendation that approving wholesale replacement would remove all historic fabric protected under the language of the ordinance. Recommendation: While fiberglass has the advantage of good molding ability to replicate decorative ornament and takes paint well, the visibility of the expansion joints if they would introduce visual breaks in the cladding material is a detail of concern. The bases of the fixtures appear to be most prone to damage from collision, which raises concerns about fiberglass as a substitute material that is fragile to impact. The existing cast iron cladding appears to be in sound condition, with rust occurring primarily at unpainted surfaces where cladding sections adjoin with one another. The Committee agreed with the department, commenting that the cast iron has held up considerably well over the past century that the fixtures have been installed and exposed to wear from both natural and man-made causes. Initially, members of the Committee commented that since the bases appear to be subject to the most direct impact from vehicle strikes, perhaps selective replacement in that location could be considered. However, in the month that the fiberglass mock-up had been installed, the fiberglass base had already been struck resulting in a visible gouge in the material and the base displaced requiring a work crew to do patch repair and base realignment. This requirement for repair 30-days after installation called into question the durability and maintenance requirements for fiberglass as opposed to the high durability of the 100-year old cast iron.  Recommendation: Because cast iron and glass are materials still readily available and that manufacturers are capable of replicating the historic light standard from molds of the original, the Department recommends that historic fabric be retained and repaired. Cast iron cladding that is beyond repair should first be replaced using historic cast iron pieces currently available at the sponsor's storage yard. Once historic pieces have been exhausted, new cast iron should be installed to match the old in design, color, texture, and other visual qualities. Should cast iron, or the craftsmen to create replacements, no longer exist then a substitute materials should be considered. The Committee agreed with the department that it did not appear to be the case that cast iron was unavailable to make repairs in-kind, as specified in the Secretary of the Interiors Standards. Recommendation: As part of PG&E's ongoing maintenance plans for the light standards, regularly scheduled inspections of the interior steel support poles and water infiltration should be conducted. Fixtures found to be in danger of structural failure should be repaired through the installation of new, sound interior steel that is protected from corrosion without altering the appearance of the historic cast iron cladding. The Committee agreed with the department that the root causes of the structural failure, based on photos provided by the sponsor showing advanced deterioration of the fixtures' internal steel poles, appear to be rust and corrosion unaddressed due to deferred maintenance. The Committee noted that, by adding weep holes at the base of the fixture, pooled water could be directed away from the base of the internal support pole. Recommendation: As examples of existing historic fabric from the period of significance of the surrounding Art. 11 Conservation District, it is recommended that the historic cast iron cladding be retained to maintain as much of the historic character of the district as is feasible.  While the Committee agreed that 100% replacement of all existing historic cast iron with new fiberglass was not a proposal they could support as meeting the Secretary of the Interior's Standards for Rehabilitation, they suggested that the sponsor might wish to create a partial-fiberglass mock-up fixture for the Committee's review. The bulk of the weight supported by the internal steel pole is focused on the upper lanterns and connecting horizontal cross-bar. Because of this, the topmost elements of the light fixtures may be eligible for selective replacement using a substitute material, if found to be beyond repair. The Committee noted that at nearly 20-feet above grade, replacement materials at the highest points on the light fixture was comparable to past Historic Preservation Commission approvals of substitute materials on building cornices at higher elevations. The Committee raised several points of concern regarding the fiberglass substitute materials, such as deterioration, difficulty of repair, and long-term weathering. The Committee discussed advancements in the material technology with the contractors. While the Committee acknowledged and welcomed these advancements as a positive trend in the field, its members still expressed concerns over how the material might perform over time. Two examples that were discussed included the base of the full-fiberglass mock-up fixture that had been struck and displaced, and showed a visible scar and discoloration of the material, with frayed fibers exposed as a result of the impact, and the cornices where substitute materials had been approved but had experienced a distinct color-shift after long-term UV sunlight exposure. Because of the relative newness of substitute materials, as opposed to cast iron which has performed well for over 100 years, the general consensus was to have the sponsor explore a more limited use of the material in a subsequent single-fixture mock-up that could be installed as a pilot program to monitor its performance, along with the 100% fiberglass fixture already installed. The Committee recommended at this time that all other fixtures should be repaired rather than replaced.

 

ADJOURNMENT – 11:22 PM
ADOPTED DECEMBER 7, 2017