GOGA_173769_Contractor_Bidwalk_RFIs.pdf

REVIEWER:DusterhoffDusterhoff

Date 19-Apr-16

To access the Utility Trench, existing covers need to be removed. These covers vary in condition and some are already broken in place. If covers are damaged during removal, is the Contractor responsible to fix and/or replace them? If so, can the Park provide details of the construction of the covers and previous methods used to repair them?

Condition of the chase covers shall be documented in advance of the construction per the division 1 requirement under SECTION 01 32 33 – PHOTO DOCUMENTATION FOR

HISTORIC PRESERVATION PROJECTS. Chase covers damaged during the construction will need to be repaired or replaced. Please see attached GOGA 173769 Appendix - Alca

Roadway Chase Cover Dwg.

Where piping material is called out (i.e. Copper, PVC, HDPE, C900) is this a requirement of the contract, or a suggestion?

We strongly recommend the use of the materials called out for on the Fire suppression documents.

4 In Attachment #1, Note #9, calls for all piping and fittings to be primed and painted. Is this for all piping on the project, or only exposed piping in the

Quartermaster’s Warehouse? Can the Park please provide a Painting

Specification?

The exposed piping on the basement, mezzanine, first and second floor below the horizontal ceiling line shall be painted.

Pipe above the ceiling line in the rafters may remain uncoated.

Color ID below:

Basement: Sherwin Williams, SW-6255 “Morning Fog”

Mezzanine, First Floor and Second Floor below ceiling level:

Benjamin Moore, OC-37 “Glacier White”

Project’s roof is sloped with a pitch exceeding 2:12. Per 2013 NFPA 13:

11.2.3.2.4 The system area of operation shall be increased by 30% without revising the density. Therefore for an Ordinary Hazard Group 2 occupancy the minimum flow required will be 1950 s.f. X 0.20 gpm = 390 gpm min. If residual flow is added -due to pressure differential-, then the expected flow required should be around 420 gpm.

Based on this, is the Proposed 300 gpm @ 85 psi Fire Pump -as noted on FP1- under rated?

Projects roof slope exceeds 2:12, Assumption of roof ridge elevation of 20' or less, use NFPA 13; fig. 11.2.3.2.3.1 and

11.2.3.2.3.3. (reduction):1500 s.f x .25% = 375 (1125 s.f):

(increase) Apply 11.2.3.2.4. 1125 s.f x .30% = 1462.5 s.f

(rounded to 1500 s.f) 1500 s.f. x .20 gpm = 300 gpm; 300

GPM Pump is acceptable.

GOGA 173769 2016_04_07 Contractor Pre Bid Walkthrough RFIs

Fire pump rating may increase to 400 gpm. Fire Pumps are required to be tested at 150% of its rated capacity, thus a 400 gpm pump will be tested at

600 gpm. A 4” UG pipe would cause a high friction loss in a system that is feed by gravity, thus the test reading would be inaccurate, not reflecting the actual conditions of the fire pump. We recommend to upsize it to 6”, if so, the existing 6” sleeves would have to be replaced.

Based on this, is the proposed 4” C900 PVC Underground piping from

Tie-in to suction side of fire pump too small for Pump flow testing purposes due to its length?

4" main piping is acceptable for the testing of the fire pump.

NFPA 24 gives direction that testing at peak of 150% should be used unless available suction supplies do not allow flowing of 150 percent. The fire pump shall be tested to the maximum allowable discharge of 450 gpm.

2013 NFPA 13: 4.12.7.1 requires pump room floor to be pitched for adequate drainage of escaping water away from critical equipment such as the pump, driver, controller, and so forth. Section 4.12.7.2 requires a floor drain that will discharge to a frost-free location. Based on this, should a floor drain be included in the area where the proposed fire pump room is to be built?

Requirement waived by NPS due to existing site constraints and elevations of equipment noted.

Consultant concludes that flow calculations estimate a minimum of 18,000 gal. water supply is required. Based on information provided on RFI #01, the minimum flow demand should be around 420 gpm, therefore the minimum water supply is (420 gpm X 60 min.) 25,200 gpm., without taking into an account the 250 gpm hose allowance required for an Ordinary Hazard Group

2 Occupancy. If the hose allowance is included, as required by the CBC, then a 40,000 gal water storage tank would be required. The existing 21,800 gal water tanks DO NOT satisfy any of the aforementioned water requirements. Based on this, could the consultant provide additional support for their water supply calculations?

18000 gal. of water supply is required and available. Hose allowance is not required per pre-design clarification letter dated 5-26-2015 with Mr. Keith Stout. Additionally, an estimated 15.0 psi is available at suction side of fire pump.

In the Solicitation Specifications, Section 21 00 00 FIRE SPRINKLER, Part

2.1 Materials F. Sprinklers:” States, “Heads to be Quick Response, Stainless

Steel with factory wax coating.” Suppliers either carry a Stainless Steel head or a wax coated head but not a “Stainless Steel with factory wax coating”.

Please specify.

Correction, should have read Stainless Steel or Wax Coated.

NOTE Fire Protection Engineer Notes provided with RFI response

Note that, as part of this effort, we have assumed that the peak of the roof is 20 feet above the top floor. I have also attached the meeting minutes from the meeting with the fire marshal if you want to share that (or the appropriate excerpt regarding hose stream) with the contractor. It is my understanding that the contractor might be concerned that omission of the hose stream from his calculation needs fire marshal acceptance/recognition.

NOTE

Excerpt from 2015_05_04 meeting with NPS Fire Marshal Stout, Fire

Protection Engineer Wolski and Parks Conservancy Project Architect Sohn.

"Water Supply - Mr. Wolski explained that he and his team, including Peak Engineering, have reviewed the current conditions and have developed a strategy. The strategy is based on utilizing the two 12,000 gallon (estimated) tanks to provide water to a new 300 GPM electric fire pump located at the 1st level of the QWB. As the QWB is expected to include storage of normal retail combustible no greater than 8 feet in height, the NFPA 13 Hazard Classification was deemed to be, at worst, Ordinary Hazard (OH) Group 2. NFPA 13 requires that the system be served by at least 60 minutes of water supply. Mr. Wolski requested and received confirmation from

Mr. Stout Meeting Notes Golden Gate National Parks

Conservancy Page 2 of 2 that 60 minutes is adequate. Mr.

Stout also agreed based on the fact that the system is served by a tank, and that manual fire fighting is unlikely, that interior or exterior hose stream allowances are not necessary in determining the duration of water supply."

NOTE Fire Protection Engineer Notes provided with RFI response

RFI item 5 would necessitate the use Quick Response (QR) sprinklers for the sloped ceiling space, however, I noticed that specific reference to QR sprinklers was missing from our response. We only provided the reference section in NFPA

13. So, I think to be 110% clear, please forward this added piece of information.

NOTE NPS

Use of scissor lift was noted as "not recommmended" during the pre-bid walkthrough due to loading concerns. Contractor may propose use of mechanical lifting equipment by providing equipment specifications sufficient to allow evaluation by the project's PE.

NOTE NPS

Three pipe sleeves were referenced and their approximate location identified during the pre-bid walkthrough. They were noted in the summary as 6" sleeves. The attached photos indicate that the sleeves are 4" and therefore not sized correctly for the 4" fire water line. The contractor will need to core an opening large enough to accept the 4" FW line.