Attachment 1 Appendix B - Basis for Design.docx

Appendix B – Basis for design

Basis of Design: The basis of design should be a bound presentation of facts sufficiently complete per the following suggested format. Detailed design computations, sizing of members or conductors, details of connections, etc., are not necessary with the basis of design, but general computations supporting system selection are required.

1. BASIS OF DESIGN - SUGGESTED FORMAT

2. The following guidance is written around new building type construction. Where a project consists primarily of mechanical, electrical, structural, or another discipline, the basis of design shall provide more detailed information for the major discipline.

3. ARCHITECTURAL

a. a. Statement of the type of construction adopted with reference to the occupancy, anticipated tenure of usage, degree of fire resistance, and maximum allowable floor areas and number of stories allowed by the Uniform Building Code.

b. Statement as to the type of thermal insulation to be provided, when required, and the value of the U factors for the various portions of the structure, i.e., roof, walls, floor, etc. Also provide description of all architectural energy conserving features to be incorporated, including any passive solar systems. Refer to the Energy Conservation Section for additional information. Refer to ASHRAE Standard 90.1 – 2016.

c. Provide a one-page narrative description of the preliminary color design concept addressing Architectural finishes and colors. Describe materials for all major items of construction and all interior and exterior finishes. The description of finishes (colors, textures, and patterns) shall be accomplished by the use of a finish schedule, color legend and notes. The finish schedule on the drawings shall identify interior building material finishes (A&E may choose room-by-room name or number format). For the completed project all reference to building colors shall be on the drawings in the color legend that is referenced to the finish schedule. Any finishes not referenced in the color code columns of the finish schedule should be in either the comment section or color notes. Provide a generic color board referencing the narrative. A description of items not considered to be a permanent part of the structure, such as workbenches, shelving, bins and removable partitions.

d. Analyze the design for compliance with latest edition of DM -01.03, Architectural Acoustics, and DM3.10, Noise and Vibration Control. Include a statement as to general adherence to the criteria. When required, list areas of high noise and vibration and acoustic design principles applied.

e. Facilities required to be accessible to physically handicapped persons shall be designed and constructed or retrofitted per the Uniform Federal Accessibility Standards (UFAS), Federal Register, (49 FR 31528 latest edition) (reference (5e)). Requirements for new construction, additions, and alterations vary and are specified in the standards. In general, all facilities worldwide which are open to the public, or to limited segments of the public, or which may be visited by the public in the conduct of normal business, shall be designed and constructed to be accessible to physically handicapped persons.

f. Analysis of Life Safety Code (NFPA 101) requirements for all occupancies involved. Determine occupancy classifications, calculated occupant load, number and size of exits and other requirements. Describe unusual or critical code requirements and indicate how such requirements will be met.

g. Describe special construction features incorporated into the facility such as barred windows, special wall/roof construction, raised computer flooring, RF Shielding, HEMP protection, etc.

h. The architect shall identify to the structural designer all partitions, i.e., non -load bearing walls (full height and less than full height), so that required strengthening can be determined. These considerations shall include seismic, wind and other dynamic loads applied to these walls. The partitions may be wood, or steel stud framed, or CMU. Appropriate control joints shall also be considered.

4. Structural:

i. Description of foundation conditions, type of foundation to be used, method by which the allowable bearing values is to be det ermined, and maximum allowable bearing capacity for the foundations. Geo-technical information including field boring notes and report of recommendations shall be submitted.

j. Statement of the type of construction adopted, and reason therefor, with capacity, dimensions, or other size criteria, and list of material selected with design strengths.

k. Special features to be included in the structure, which are not evident from the drawings.

l. Description of the structural floor and roof systems proposed, with length, spacing and size of principal members (for beam and girder, etc.).

m. Description of the Lateral Force Resisting System proposed with appropriate materials and dimensions.

n. Statement of live loading to be used, to include floor loads, wind, snow, earthquake, etc., with data to justify.

o. Statement of any special considerations that affect the design (e.g., super flat floors for high stacking warehouses, special corrosion resistance requirements, retractable roofs, etc.).

p. Contact the cognizant PM for extent of crane design required. Include special considerations as to crane and monorail requirements; i.e., special architectural -structural considerations, area of service, and type of system.

i. The usual accepted means of structural system selection is economy. Demonstrate this with computations of various appropriate framing systems and cost comparisons of each, including:

i. Typical bay member sizing and cost comparisons of alternate structural systems;

ii. Horizontal force resisting system for wind and earthquake;

iii. Consideration of unusual geometry (long span, high bay, deep cuts, etc.);

iv. Consideration of heavy equipment supports.

5. Civil:

a. Provide site plan showing layout and utility connections.

6. Environmental Construction and Operating Permits:

a. Identify with a narrative description the pollution that will be generated on -site during construction and a proposed method that can be specified to control the pollution. A detailed description of construction pollution control shall be outlined in the basis of design for air pollution, pollution to ground and surface waters and the central prohibited discharges to on-site sewage systems. Provide as appropriate the elements proposed for final design needed for a Storm Water Pollution Prevention Plan.

b. Environmental Operating Permits - Identify by a narrative description each of the permits needed to operate the proposed design. Identify assumptions and limitations that are proposed as a basis for design. Address discharge limitations of air and water pollution with regard to regulatory requirements. The above requirement is particularly related to designs for incinerators, sewage plants, water plants, industrial process facilities, power and heat generator facilities, and solid waste handling facilities.

c. Design of Oil Spill Prevention Control and Countermeasures (SPCC) systems shall be per Federal Register, Title 40, Part 112 titled Oil Pollution Prevention.

7. ASBESTOS, LEAD BASED PAINT, AND HAZARDOUS MATERIALS

The A&E shall investigate for the presence of asbestos, lead or hazardous materials that will be disturbed in any way by the proposed work. This investigation shall be performed by a State of Florida Accredited Asbestos Inspector and shall identify any suspected material that appears to be involved in the proposed work. The A&E shall determine the scope of the investigation, using information in the VA guide specifications as guidance, and enlisting the advice of consultants. The project architect should develop scope for miscellaneous building materials, the mechanical engineer for HVAC and process systems, and the electrical engineer for power manholes and other wiring systems. It is important to realize that debris from one discipline's work can adversely affect the work of others. A certified testing laboratory will be used to sample and test the suspected asbestos, lead based paint or hazardous materials. However, the Asbestos Inspector and the A&E shall review the work of the laboratory and require additional tests that may be required to fully determine the extent of the asbestos, lead based paint or hazardous materials. Change orders for additional testing are appropriate. Provide a signed report certifying the investigation. The report shall be certified by the Asbestos Inspector and shall include the Inspector's certification number. Distribution and number of copies of this report will be provided by the PM in the A&E's contract Appendix A. If asbestos, lead based paint or hazardous materials are found, the A&E shall indicate the extent of asbestos, lead based paint or hazardous material removal in the project documents and specify removal procedures per applicable regulations and in sufficient detail for the contractor to submit an accurate bid. (Note - Pipe insulation shall be indicated by major systems on as -built type drawings, etc.). If testing is performed and the material does not contain asbestos or lead based paint, add a note on the drawings to the effect.

8. For asbestos removal, several different cleanup scenarios are presented:

a. Complete Cleanup: A project is scoped for removal of all asbestos bearing materials within a crawl space. In this case, the A&E shall be requested to take asbestos insulation samples (pipe coverings), soil surface contamination samples (debris), and soil contamination samples. The results from testing the soil and soil surface contamination samples will be used to determine the scope of cleanup operations. One alternative to consider when soil contamination occurs would be to determine if the debris trail follows a geometric pattern; i.e., only under the pipe runs. If this is true, it might be more economical to treat those areas, only, by removal. However, the requirement for soil removal should be backed by laboratory tests and proper interpretation of the law as it pertains. If soil surface contamination exists, removal of the debris, only, may be adequate if subsequent air and soil samples indicate an acceptable environment. If contamination is not found, the following statement shall be placed on the drawings beside the crawl space: "Soil (debris) has been tested and found to be asbestos free." When soil samples show contamination, the statement, "Soil (debris) is contaminated with asbestos" shall be used. Similar situations occur in other areas of a building, such as mechanical rooms, attics and high truss areas, and spaces between floors. In attics, the ceiling and/or the insulation above it would be treated like the soil previously mentioned. The appropriate statement would then have the format: "The ____________ area is contaminated with asbestos (debris)."

b. Partial Cleanup: A project where insulation has been tested as required and some asbestos has been found, and only the pipes/materials being worked on will be reinsulated or removed and replaced. This could happen in a crawl space, attic, mechanical equipment room, high truss area above ceilings, pipe chases and other areas. In these cases, the following note shall be placed on the plumbing or mechanical drawings, as well as drawings of other disciplines, which will be performing work in area: "Asbestos is present in the ______________ area. Protect all personnel within this asbestos area during the entire construction period by complying with 29 CFR 1926.58." Also when appropriate, along with the 35% submittal, address a letter to the VA with the following comments: "Asbestos laden pipe insulation was found during sampling on the following lines and it is likely that asbestos insulation exists beyond the limits of this project." Then list the pipelines involve d. A similar scenario would be appropriate for new electrical work in existing manholes. Cables that are not to be worked on need not be cleaned. However, the contractor must be warned about the potentially hazardous environment.

c. No Cleanup: A project where the building is older than 1975 and no work is to be done on existing piping or asbestos suspected materials (i.e., apparently no testing required). However, the A&E should consider that, when running new piping or conduit in an older building, the existing finish materials that require drilling and cutting to allow the work to pass, or the spaces, especially attics and crawl spaces, through which the work must pass may be asbestos contaminated. Testing should be done, and the existing asbestos identified. In this scenario, the same note shall be applied to the drawings as if it was a Partial Cleanup: "Asbestos is present in the _______________ area. Protect all personnel within this asbestos area by complying with 29 CFR 1926.58."

d. Total Demolition: A project where a building or facility is to be demolished and the site readied to receive a new building or facility. Each possible building material that historically could have been an asbestos based material should be tested. Instances of asbestos contamination should be clearly indicated, by specific building system, with special care taken to include any secondary contamination that might have occurred due to debris from that system. If a specific system indicates a tendency toward a asbestos contamination, then the entire system should be so treated. Also, in facilities scheduled for demolition, investigation should be made to find sources of hidden asbestos.

9. If the A&E decides to obtain the services of an outside testing organization to assist in defining the asbestos related work, the emphasis should be on an organization that can provide in-house engineering. They should be capable of using engineering judgment and experience to search out suspected sources of asbestos, with the initiative to suggest further testing when required, and the knowledge and experience with the EPA directives to interpret them and suggest the most financially efficient cleanup methods. They should also be capable of producing detailed engineering drawings delineating the extent of the asbestos removal effort required, in a biddable format, and professionally seal these drawings themselves.

10. Water Supply

a. Describe the existing system, indicating particularly the type, capacity, condition, present water use, and unsatisfactory elements.

b. State type of construction proposed, materials for water mains, type of well, etc.

c. For exterior distribution systems, state design parameters including domestic and fire flow, residual pressure, elevation differentials, etc. Include designer's initial estimate of pipe sizes. For projects geographically located within the Continental United States coordination with the appropriate State Regulatory Agency is required.

d. State tentative sizes, elevations, capacity, etc., as can readily be determined without long computations or design consideration for reservoirs, treatment units, pumping stations, well pumps, and such units

11. Sewage and Sewage Disposal Systems

a. Describe the existing system indicating particularly the type, capacity, condition, present flow, and unsatisfactory elements. Address the adequacy of the downstream sewers for capacity and of the pumping station to prevent overflows including alarms, power, and assumed response time by the base operations staff.

b. Describe the degree of treatment and each of the unit processes proposed. Address the operational requirement related to the selected type of treatment.

c. State design factors with present and projected design population loads for sewage treatment plants. For projects geographically located within the Continental United States, coordinate with the PM for special meetings and submissions to the State Regulatory Agencies.

d. State materials to be used for sewer systems and sewage treatment plants.

e. Identify standards (Federal, State, local) governing the design.

f. Describe the impact of steam condensation and cooling water discharges on existing sewer piping and sewage treatment plants and the estimated cost of distribution and treatment of this additional loading. Analyze the discharge alternatives for industrial wastewater related to a direct discharge, no discharge or a discharge to the sanitary. Provide a cost-based solution considering applicable environmental regulations.

12. Roads, Driveways, Parking Areas and Walks:

a. State general soil conditions, with a brief outline of soil exploration and testing performed.

b. Describe the type and volume of traffic, controlling wheel loads and types or classes of roads under consideration with justification for any deviation from criteria thicknesses for these classes.

c. Evaluate existing pavement conditions for reuse. Indicate residual structural valves for each differing pavement.

d. Note condition of adjacent drainage features.

13. Dust and Erosion Control

a. Dust and erosion control, where deemed necessary, will be considered an integral part of all design and construction projects. Such controls will be generally limited to areas scarred or denuded in the process of constructing a project. Dust and erosion control will not be confused with landscaping. The 35% submittal will contain the necessary design data, outline specifications, and costs for dust and erosion control measures where applicable. The Basis of Design will include a statement regarding the type of treatment selected, affecting areas, and reasons for selection of type and determination of areas.

14. Cathodic Protection and Protective Coatings

a. Cathodic Protection (CP) is required for all underground or submerged structures on which corrosion may have severe environmental or structural effects or significant economic impact.

b. Types of structures for which the installation of CP and protective coatings is required by Federal Regulations include, but may not be limited to:

i. Underground Fuel Storage Tanks (40 CFR 280 and 281)

ii. Fuel and POL Pipelines (49 CFR 195)

iii. Natural Gas Pipelines (49 CFR 192)

iv. Liquefied Natural Gas Facilities (49 CFR 193)

15. Storm Water Management Plan

a. State what management plans are required.

16. Plumbing:

a. Determination of number of each type of fixture based upon the number of persons to be served.

b. Estimated number of fixture units and water demand in GPM for all plumbing fixtures.

c. Estimated maximum and minimum water pressure at each building and indicate if booster pumping will be required.

d. Type, size, and design temperature of domestic water heater and distribution system. Also, a statement as to whether heat recovery is contemplated for domestic water heating.

e. Design temperature of domestic hot water distribution system and extent of recirculation system within building.

f. Provide a description of any special mechanical systems such as compressed air, hydraulic, nitrogen, etc., including an explanation of the medium source.

17. Heating, Ventilation and Air Conditioning:

a. Use the following conditions in software calculating the space cooling and heating loads:

i. Cooling (critical facilities such as inpatient wards, nursing home care, OR research labs, etc.) – 0.4% Dry-bulb and mean coincident wet bulb temperatures).

ii. Heating (critical facilities such as inpatient wards, nursing home care, OR research labs, etc.) – 99.6% Dry-bulb and mean coincident wet bulb temperatures).

iii. Cooling (non-critical facilities such as offices, warehouses, central laundry etc.) – 1.0% Dry-bulb and mean coincident wet bulb temperatures).

iv. Heating (non-critical facilities such as offices, warehouses, central laundry etc.) – 99.0% Dry-bulb and mean coincident wet bulb temperatures)

b. Use the following conditions for air handling unit mixed air calculations and for sizing heating coils, cooling coils, and humidifiers:

i. Cooling (100% outdoor air unit) – 0.4% wet bulb and 0.4% dry-bulb. • Pre-Heating (100% outdoor air unit) – Mean of minimum annual extremes temperature.

ii. Cooling (Units with recirculation serving in-patient facilities) – 0.4% Dry-bulb and mean coincident wet bulb temperatures.

iii. Heating (Units with recirculation serving in-patient facilities) – 99.6% Dry-bulb temperature.

iv. Cooling (All other units with recirculation) – 1.0% Dry-bulb and wet-bulb temperatures.

v. Heating (All other units with recirculation) – 99.0% dry-bulb temperature.

vi. All Humidifiers: 99.6% Humidification dew point and mean coincident dry-bulb temperatures. See ASHRAE Handbook of Fundamentals 2013 or approved latest edition.

18. Electrical:

a. It is the responsibility of the A/E to prepare and submit, or specify calculations, study and analysis as required by the type of design work performed. Calculations shall justify electrical designs; size of each conductor, raceway, overcurrent protective device, equipment bus, generator, transformer, etc.; setting of each overcurrent protective device with adjustable characteristic; required PPE to meet arc flash energy levels; etc. It is the responsibility of the A/E to determine which calculations to perform and which calculations to specify for the Contractor to perform. Not all calculation types shall be required for all projects. VA reserves the right to request additional calculations to suit the project.

b. The selection of specific electrical power equipment manufacturer in the design phase is likely to occur only in unusual circumstances with the intent to mitigate urgent VA needs. If specific electrical power equipment manufacturer is selected during the design phase, the A/E shall prepare and perform Fault Current, Protective Device Coordination, and Arc Flash calculations, study and analysis. The A/E shall use the Master Specification Section 26 05 73, OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY, as a basis to perform these tasks. The A/E shall provide written reports of all calculations, study and analysis to VA and the Contractor. The A/E shall coordinate and collaborate with VA, the Contractor, and the selected equipment manufacturer in setting and adjusting the electrical power equipment according to the results of the calculations, study and analysis. The purpose is to ensure that the manufacturer’s equipment functions and operates safely as intended.

c. However, in a typical VA major and renovation project, electrical power equipment manufacturer is not selected during the design phase. Selection of electrical power equipment manufacturer occurs during the construction phase, and this information is not available to the A/E during the design phase. Due to the different electrical characteristics of different manufacturers of the same equipment, not knowing the selected equipment manufacturer during the design phase impedes the A/E’s ability to perform the Protective Device Selective Coordination and Arc Flash calculations and analysis effectively. In order to mitigate this issue, the A/E shall include Master Specification Section 26 05 73 in the construction contract document, and follow additional guidance listed in Sections 1.10.2, 1.10.3 and 1.10.4. 1

d. FAULT CURRENT CALCULATIONS: The A/E shall prepare and submit calculations for all new projects, and renovation projects to existing electrical distribution systems at the design phase. The available fault currents shall be included on the one-line diagram and/or riser diagrams and shall show the available fault current (expressed in amperes, RMS symmetrical) at each bus and electrical equipment such as switchgears, switchboards, distribution panelboards, panelboards, overcurrent protective device and transformer in the system. Supporting calculations (such as those resulting from a SKM PowerTools™ analysis) that justify the summary available fault currents on the one-line diagram and/or riser diagrams may be submitted to VA separately in 8.5" x 11" format.

e. PROTECTIVE DEVICE COORDINATION CALCULATIONS: Unlike Fault Current calculations, Protective Device Coordination calculations and study is dependent on specific electrical data produced by the selected electrical equipment manufacturer. The A/E is unlikely to perform this task accurately and effectively without knowing the selected electrical equipment manufacturer in the design phase. Therefore, in a typical VA major and renovation project, the A/E is not required to perform the Protective Device Coordination calculations and study during the design phase. However, the A/E shall include the Specification Section 26 05 73 in the construction contract document. During the submittal review period in the construction phase, the A/E shall perform submittal review and analyze contractor’s submittals required in the Specification Section 26 05 73. The A/E shall inform VA of any deficiency in calculations and reports shown in the submittals that potentially affect the safety and function of the systems. The A/E shall recommend mitigating actions to VA, if needed. The A/E shall coordinate and collaborate with VA, the Contractor, and the selected equipment manufacturer in setting and adjusting of the protective devices and related equipment to ensure safe and functional systems.

f. ARC FLASH CALCULATIONS: Arc Flash calculations and analysis is dependent on the results of the Protective Device Coordination calculations and study. Notably, the actual protective device clearing time is essential for Arc Flash calculations and analysis. Therefore, in a typical VA major and renovation project, the A/E is not required to perform the Arc Flash calculations and analysis during the design phase. However, the A/E shall include the Specification Section 26 05 73 in the construction contract document. During the submittal review period in the construction phase, the A/E shall perform submittal review and analyze the Contractor’s submittals required in the Specification Section 26 05 73. The A/E shall inform VA of any deficiency in calculations and reports shown in the submittals that potentially affect the safety and function of the systems. The A/E shall recommend mitigating actions to VA. The A/E shall coordinate and collaborate with VA, the Contractor and selected equipment manufacturer in the process of finalizing information for arc flash calculation and analysis.

g. LOAD CALCULATIONS: Prepare and submit load calculations that justify the size of each branch circuit and feeder, overcurrent protective device, transformer, and equipment bus (panelboard, switchboard, switchgear, automatic transfer switch, etc.). Calculations shall be performed at all voltage levels. The method of calculation shall be clearly presented in the drawings, including all applicable NEC diversity factors and non-coincident loads and their employment at various levels of the electrical system, as well as the capacity reserved for future load. Calculations may be in panel schedule and switchboard schedule format. It shall be possible for the VA reviewer to follow the load flow from the lowest level to the highest level of the riser and one-line diagrams.

h. GENERATOR SIZING CALCULATIONS: Prepare and submit calculations that justify the size of each generator or paralleled fleet of generators, including but not limited to all loads downstream of the generator set(s) and the sizing impacts of proposed load steps, significant motor loads, non-linear loads, and capacity reserved for future loads. If applicable under NEC Article 517, prudent demand factors and historical data used to justify generator set(s) sizing shall be clearly presented.

i. VOLTAGE DROP CALCULATIONS: Prepare and submit calculations demonstrating compliance with the following voltage drop limits: 2% for feeders and 3% for branch circuits, taken at design load.

j. HARMONIC DISTORTION CALCULATIONS: For Energy Center projects only. Prepare and submit calculations estimating the voltage and current total harmonic distortion (THD) for buses rich in non-linear loads, typically Energy Center switchboards which feed large horsepower pump motors controlled by adjustable speed drives. Use these calculations to justify active or passive components to mitigate harmonic distortion.

k. LIGHTNING PROTECTION CALCULATIONS: Prepare and submit calculations as described in Annex L Lightning Risk Assessment of NFPA 780