Product Evaluation and Approval

Transcription

1 Product Evaluation and Approval One of the biggest obstacles of current modular skylight solutions is of a consistent quality. Buildings are subject to plan reviews by building officials prior to permitting and installed products are evaluated according to standardized tests for compliance with building codes. These approval processes are necessary for assurance that the product will not adversely affect the life and safety of the building occupants and to achieve consistent and predictable performance out of the product installed. PLAN REVIEW BY BUILDING OFFICIALS Plan reviews are normally conducted by the Building Department of the permitting agency. Building design and the proposed systems are evaluated for their compliance with minimum code requirements. For Skylight systems, a primary area of concern can be how to maintain the fire resistive aspects of the building design. Penetrations, such as a skylight well, through a fire resistive ceiling/roof assembly must not adversely affect the fire-resistive integrity of the assembly. The Building Code requires these penetrations to be either fire rated for this application, or contained within a fire resistive shaft enclosure. In a skylight well system, available options can be 31 : Manufacturing a skylight well system of equivalent performance to a fire-rated shaft. Using non-fire-rated materials and methods for the skylight well that are either contained in, or integrated within, a fire-rated shaft enclosure. When products are evaluated by the International Code Council Evaluation Service (ICC- ES) or by listing agencies, the results should be included among the factors in the permitting agency review and approval. It is important to note that a product evaluation report or product listing may not guarantee acceptance of that product or system for application in all buildings. A product must be evaluated for the specific building use and type of construction for which it is intended. 31 Based on phone interview with Pete Guisasola, building official with Rocklin (California) Building Department on June 5, HESCHONG MAHONE GROUP 42

2 In the state of California, the educational buildings come under the jurisdiction of the Division of State Architects (DSA). The approval of school buildings is done by the DSA and is based on the California Building Code requirements 32. INTERNATIONAL CODE COUNCIL EVALUATION SERVICES (ICC-ES) In February 2003, the International Code Council (ICC) was formed. It is the consolidation of three major code bodies: the Building Officials and Code Administrators International (BOCA), International Conference of Building Officials (ICBO) and Southern Building Code Congress International (SBCCI). Subsequently, product evaluation services offered by these organizations, including the ICBO Evaluation Services, are now consolidated into the ICC- ES. Products undergoing ICC-ES evaluations will be evaluated against the most recent version of the International Building Code (IBC). Since existing building codes in the United States, including the state of California, are still based on the UBC, evaluations for compliance against the UBC may be requested for an additional fee 33. It is recommended that manufacturers interested in marketing to states based on the UBC avail of this additional evaluation service. Submittals required for evaluation include drawings, plans, specifications, and calculations sealed by the design professional. Each product will be evaluated according to Acceptance Criteria (AC) developed specifically for the product type. The Acceptance Criteria lists the relevant code sections and ASTM tests that are required for the evaluation for the product. Acceptance Criteria relevant to the modular skylights are: AC 16 for plastic skylights AC 17 for glass skylights, and AC 78 for skylights with plastic frames Evaluation Reports of existing modular skylight well products indicate that the performance of the unit skylight is the overwhelming criteria for product approval. Modular skylight kit of parts systems might be considered pre-fabricated building components. Applications for pre-fabricated building components should include plans and specifications differentiating between the field- and factory-installed items 34. Code Requirements Prior to the development of the ICC, building safety codes were regional. BOCA National Codes were used mostly in Eastern and Great Lakes states; ICBO Uniform Codes in Western and Midwest states; and SBCCI Standard Codes in Southern states. States are being encouraged to use the ICC International Building Codes without adaptations and revisions and at present. For a list of code requirements listed in the AC 16 and AC 17 documents, see Appendix Based on interview with Division of State Architects, Sacramento 33 Based on phone interview with Nic Horezcko of the International Code Council Evaluation Services, on April 28, Ibid. HESCHONG MAHONE GROUP 43

3 Applicable Tests As part of compliance with the code requirements and for ICC evaluation, the skylight product has to undergo various tests. Test evaluations should be conducted by a third-party entity complying with ICBO ES Acceptance Criteria 85 (AC85) and accredited by the International Accreditation Service (IAS) or by an accreditation body that is a signatory to the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement. For a list of testing standards required by code and ICC evaluation, see Appendix 6. FUTURE EVALUATION STANDARDS Current products in the market are mostly skylight wells of a maximum dimension of 22. As a result, no additional evaluation criteria were required for the well performance. With our proposal for development of systems with bigger skylight wells with heavier and more complex components, there is a need for more comprehensive evaluation criteria to ensure that skylight wells perform in a safe manner. Some important safety and fire issues that should be addressed in future evaluations include: Well connections to building structure and other lateral supports should be of adequate strength to ensure that well will not fall and cause injury to occupants. Well connection to structure should be properly designed to prevent separation or disassembly during seismic events. Fire protection requirements, such as sprinkler head installations and smoke detection equipment, should be addressed. Fire and smoke issues should be addressed, especially for fire-rated roof assemblies. Materials should be evaluated for longevity and weathering effects. PERFORMANCE METRICS There is no set standards and regulations concerning the performances of these systems. An ICBO product evaluation would satisfy concerns regarding the health and safety issues associated with a product installation, but there are no metrics for determining daylighting performance of skylights. Designers have strongly expressed a need for comparing performance of skylight systems. Having this information on hand will allow them to make intelligent decisions regarding trade-offs in design, installation, cost and performance. It also allowed them to minimize the performance-related risks associated with skylight systems. Some of the performance metrics that will help designers in decision-making: Photometric reports and files Effective aperture Fire rating Light Diffusion (in haze) as tested according to ASTM D1003 HESCHONG MAHONE GROUP 44

4 Conceptual Systems This section of the report deals with a brief description of four examples of a modular skylight systems design. System 1 is described in details with following the step-by-step design process for a modular system outlined in the guideline. SYSTEMS DESCRIPTIONS System 1: Flexible threaded rod Throat -Fixed Splay System Figure 43: Conceptual diagram of Flexible threaded rod Throat -Fixed Splay System The conceptual design of this skylight system is a flexible throat component along with a fixed splay component. The flexibility in the throat can be achieved with the help of pivoted rods on four sides of the throat. Pivoted Rods: These pivoted rods can help reserve the space for the throat so that the rest of the system design can be done based on these boundaries. The rods are designed to change positions if needed by being pivoted to connectors at the top and the bottom. HESCHONG MAHONE GROUP 45

5 Connectors: The connectors on top are adjustable that can bolt the rods from top. These connectors can also serve as a connection between the throat and the curb or the throat and the roof deck. The bottom connectors are L-shaped bars with slots at every 3 6 where the pivoted rods could be bolted on to. Splay: This system has a fixed splay component where no changes can be made to the splay angle or height for coordinating with other systems. Once the pivoted rods have been placed in the system, the splay can be fixed on to the L-shaped bars Throat material: Once the splay has been fixed on to its position and once the pivoted rods have been adjusted based on the splay position, the throat can be constructed either out of metal, gypsum board, ceiling tiles, fabric etc. Construction scheduling: In construction scheduling phase, the first step in this system is the placement of the pivoted rods, then placement of splay to ceiling tiles and then placement of the throat. System 2: Fixed Metal Throat Adjustable Splay System Figure 44: Conceptual diagram of Fixed Metal Throat Adjustable Splay System In this conceptual design, the throat is a fixed component while the splay is adjustable. However, the throat inter-connector has the flexibility to be adjusted to any throat height. In this example, the first stage of this system is the placement of throat, its connection to the curb/roof deck and to the throat inter-connector piece. Once the throat is placed, the asymmetric splay is then connected to the ceiling and the throat. The throat inter-connector has slots of a certain length that allows for vertical adjustment with the throat. HESCHONG MAHONE GROUP 46

6 System 3: Tubular Adjustable Throat Fixed Splay System Figure 45: Conceptual diagram of Tubular Adjustable Throat Fixed Splay System This tubular skylight concept consists of a flexible tubular throat that has the ability to be adjusted horizontally and vertically. The tubular throat is made of multiple adjusters like the curb-flashing connector, angle adapter, main body-the tube, and finally at the bottom the tube to square adapter that can be connected to the diffuser (if any) and the splay. HESCHONG MAHONE GROUP 47

7 System 4: Fixed Throat Flexible Connector Fixed Splay System Figure 46: Conceptual diagram of Fixed Throat Flexible Connector Fixed Splay System This system is based on the concept of a flexible throat-splay connector. This connector can be a flexible tube or a flexible and stretchable fabric that can be adjusted to any angle, both vertically and horizontally based on the position of the throat and the splay. Both the throat and the splay are fixed and installed at the same time based on the gridlayout. The connector is fixed to the throat and splay at the end so that it can accommodate its position based on the position of the throat and the splay. SAMPLE PROJECT This section describes a step by step approach to the design of one modular skylight system. The conceptual design of this skylight system has been described in section System 1: Flexible threaded rod Throat -Fixed Splay System. Schematic Design The schematic design involves the input of building and light well details into the skycalc software to calculate SFR and well efficiency, followed by spacing of skylights in the room Stage 1: Building Characteristics Occupancy type: The building type used for this example is an office space in Sacramento, California. HESCHONG MAHONE GROUP 48

8 Dimensions of room: One room in the office for which the skylights are being designed is of dimensions 60 ft x 72 ft. Other building details are: - Ceiling height: 11 ft, - Roof height: 17 ft, - Plenum height: 6 ft - Approximate spacing of sprinklers: 8 ft x 8 ft or 10 ft x 12 ft - Electric light layout: pendant mounted direct/indirect fixtures Stage 2: Light well Design Assumptions At this stage, some assumptions are made on the number and dimensions of the skylight wells along with a rough estimate of the SFR (equal to or less than 5% based on the energy code). The assumptions of the light well are as follows: Skylight size: 4 ft x 4 ft Skylight well height: 6 ft Throat height: 3 ft Splay height: 3 ft Splay angle: 45 Diffuser Yes (visible transmittance of 80%) Splay and throat reflectance: 80% Number of skylight: 9 Figure 47: Skylight well dimensions Stage 3: Skycal Software Simulation Skylight to floor ratio (SFR) The building characteristics and details of skylight well assumptions were input in the Skycalc software to get the skylight to floor ratio (SFR) and to calculate the well efficiency of the light well. The SFR based on the given skylight size and number was calculated to be 3.3%. The data entered in the skycalc is given in Figure 48. If the design requires an SFR of higher than 3.3%, the skylight dimensions and number can be altered. For example for a 4 ft HESCHONG MAHONE GROUP 49

9 x 4 ft skylight size and 9 in number, the SFR is 3.3%. If the number of skylights is increased to 12, the SFR becomes 4.4%. In order to maintain the SFR as 3.3% and increase the number of skylights from 9 to 12, the size of skylights can be reduced to 3 ft x 4 ft. Select Location Sacramento CZ 12 Skylights: Climate data loaded = Sacramento, CA Number of skylights 9 Climate data for location is already loaded Skylight width 4 ft Skylight length 4 ft Current Skylight to Floor Ratio = 3.3% Skylight Description Building Glazing type Acrylic Building type Office Glazing layers Double glazed Bldg area 4,320 ft 2 Glazing color Clear prismatic Ceiling height 11 ft Wall color Off-white paint Skylight Well Light well height 3 feet Shelving/Racks or Partitions? Well color White paint Safety grate or screen Partitions, Shelves/Racks, None/Open Yes, No Partition height 5 ft No data required 8 ft Heating and Air Conditioning Systems Cubical width 8 ft Air Conditioning Mechanical A/C Cubical length 8 ft Heating System Gas/Oil Furnace Check Lighting Power Density on Optional_Input tab Electric Lighting Utilities Lighting system Direct/Indirect fluorescent Average Elec Cost $0.117 kwh Fixture height 9 ft Heating Fuel Units Therm Lighting control Dimming min 20% light Heating Fuel Cost $0.608 /Therm Figure 48: Data inputs in Skycalc to get the SFR Well Efficiency (or Well factor) To calculate the well efficiency of light well, two light well conditions have been presented here: Condition 1: Light well with splay Condition 2: Light well without splay Condition 1: Light well with splay Well Efficiency for a light well can be calculated by two methods: the skycalc software input and hand calculations. HESCHONG MAHONE GROUP 50

10 Hand calculations The well efficiency of the skylight well can also be calculated using the equation as per the 2005 Building Efficiency Standards 35 : Well Cavity Ratio (WCR) = [2.5 x well height x well perimeter] {Well area} WCR of throat (throat ht 3ft, 4x4 dimensions) = {2.5 x 3 x 16}/ {16} = 7.5 WCR of splay = {2.5 x 3 x 40}/ {100} = 3 Well efficiency (or well factor-wf) of a light well can be located based on the WCR and the reflectance of the light well surface as shown in Figure 49. Well efficiency for throat (WE throat) = 66% Well efficiency for splay WE splay = 87% Tvis diffuser = 80% Well Efficiency Reflectance = 40% Reflectance = 80% 60% Well Cavity Ratio (WCR) Reflectance = 99% Reflectance = 90% 70% Figure 49: Well efficiency graph Well efficiency for the entire light well (see Figure 50) = WE1 (throat) x WE2 (splay) x Tvis of diffuser = 0.67 x 0.87 x 0.80 Well Efficiency for light well with splay = 45% Building Energy Efficiency Standards. Standards for residential and Non residential buildings February Draft 3. California Energy Commission HESCHONG MAHONE GROUP 51

11 Figure 50: Total well efficiency of light well with splay (WE1 x WE2 x Tvis of diffuser) Skycalc Calculations To get the well efficiency of a light well with splay using skycalc, 2 separate skycalc runs need to be made- one for the throat and the other for the splay. In case of the input for the throat, the dimensions of 4 x 4 are put along with a well height of 3 ft. The resulting well efficiency of the throat (or Well factor) was calculated by skycalc as 68% as shown in Figure 51. HESCHONG MAHONE GROUP 52

12 Skylights Default User Revisions Design Input Visible transmittance 59% 59% Solar heat gain coefficient 53% 53% Curb type Wood Default Wood Frame type Metal w/ thermal brk Default Metal w/ thermal brk Unit U-value (Btu/h F ft 2 ) Dirt light loss factor 70% 70% Screen or safety grate factor 100% 100% Light well reflectance 80% 80% Well factor (WF) 68% 68% Bottom of light well: Width (ft) Length (ft) Yes, No Diffuser on bottom of well? No Yes Building Default User Revisions Design Input Building width (ft) Building length (ft) 93 Change width or area 72 Wall reflectance 70% 70% Ceiling reflectance 70% 70% Floor reflectance 20% 20% Shelving reflectance 40% 40% Roof U-value (Btu/h F ft 2 ) Electric Lighting Default User Revisions Design Input Lighting setpoint (fc) Task height (ft) Lighting power density (W/ft 2 ) Fraction lighting uncontrolled 10% 0.10 Lighting schedule Office Default Office Room and luminaire depreciation 80% 80% Figure 51: Well efficiency of throat using Skycalc Well efficiency for splay was calculated by skycalc using the input values of 10 x 10 for splay area (to be input in user revisions column in the skycalc worksheet) and a height of 3 ft. The well efficiency of splay was calculated by the skycalc as 87% as shown in Figure 52. HESCHONG MAHONE GROUP 53

13 Skylights Default User Revisions Design Input Visible transmittance 74% 74% Solar heat gain coefficient 67% 67% Curb type Wood Default Wood Frame type Metal w/ thermal brk Default Metal w/ thermal brk Unit U-value (Btu/h F ft 2 ) Dirt light loss factor 70% 70% Screen or safety grate factor 100% 100% Light well reflectance 80% 80% Well factor (WF) 87% 87% Bottom of light well: Width (ft) Length (ft) Diffuser on bottom of well? No Yes, No No Building Default User Revisions Design Input Building width (ft) Building length (ft) 93 Change width or area 72 Wall reflectance 70% 70% Ceiling reflectance 70% 70% Floor reflectance 20% 20% Shelving reflectance 40% 40% Roof U-value (Btu/h F ft 2 ) Electric Lighting Default User Revisions Design Input Lighting setpoint (fc) Task height (ft) Lighting power density (W/ft 2 ) Fraction lighting uncontrolled 10% 0.10 Lighting schedule Office Default Office Room and luminaire depreciation 80% 80% Figure 52: Well efficiency of splay using Skycalc The total well efficiency of the light well with splay is: = WEthroat x WEsplay x Tvis of diffuser =.68 x.87 x.8 = 47% Figure 53 and Figure 54 present the total annual energy savings and cost savings based on the well efficiency of 47%. HESCHONG MAHONE GROUP 54

14 6,000 Total Annual Energy Savings from Skylights Lighting, Cooling and Heating (all fuels converted to kwh) 5,000 Annual Energy Savings (kwh/yr) 4,000 3,000 2,000 1,000 Design 0 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% -1,000 Skylight to Floor Ratio (SFR) Figure 53: Total annual energy savings from skylights (Kwh/yr) $900 Total Energy Cost Savings from Skylights for Lighting, Cooling and Heating Annual Cost Savings ($/yr) $800 $700 $600 $500 $400 $300 $200 $100 Design $0 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% Skylight to Floor Ratio (SFR) Figure 54: Total energy cost savings from skylights ($/yr) Condition 2: Light well without splay In order to get the same SFR of 3.3%, the size of the skylights will change from 4 ft x 4 ft to 3 ft x 4 ft and the number of skylights are 12 instead of 9. Hand Calculations Well Cavity Ratio (WCR) = [2.5 x well height x well perimeter] Well efficiency = 43% [Well area] = {2.5 x 6 x 14}/ {12} = 17.5 Skycalc Calculations According to the Skycalc calculations, the well efficiency (or well factor) of the light well without splay was calculated to be 42% as shown in HESCHONG MAHONE GROUP 55

15 Skylights Default User Revisions Design Input Visible transmittance 59% 59% Solar heat gain coefficient 53% 53% Curb type Wood Default Wood Frame type Metal w/ thermal brk Default Metal w/ thermal brk Unit U-value (Btu/h F ft 2 ) Dirt light loss factor 70% 70% Screen or safety grate factor 100% 100% Light well reflectance 80% 80% Well factor (WF) 42% 42% Bottom of light well: Width (ft) Length (ft) Diffuser on bottom of well? No Yes, No Yes Building Default User Revisions Design Input Building width (ft) Building length (ft) 93 Change width or area 72 Wall reflectance 70% 70% Ceiling reflectance 70% 70% Floor reflectance 20% 20% Shelving reflectance 40% 40% Roof U-value (Btu/h F ft 2 ) Electric Lighting Default User Revisions Design Input Lighting setpoint (fc) Task height (ft) Lighting power density (W/ft 2 ) Fraction lighting uncontrolled 10% 0.10 Lighting schedule Office Default Office Room and luminaire depreciation 80% 80% Figure 55: Well efficiency of light well without splay using Skycalc 5,000 Total Annual Energy Savings from Skylights Lighting, Cooling and Heating (all fuels converted to kwh) 4,000 Annual Energy Savings (kwh/yr) 3,000 Design 2,000 1, % 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% -1,000 Skylight to Floor Ratio (SFR) Figure 56: Total annual energy savings from skylights-light well without splay (KWh/yr) HESCHONG MAHONE GROUP 56

16 $900 Total Energy Cost Savings from Skylights for Lighting, Cooling and Heating Annual Cost Savings ($/yr) $800 $700 $600 $500 $400 $300 $200 $100 Design $0 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% Skylight to Floor Ratio (SFR) Figure 57: Total energy cost savings from skylights-light well without splay ($/yr) Stage 4: Skylight Spacing Skylight spacing was then calculated using the rule of thumb for both conditions (light well with and without splay). Condition 1: Skylight with splay Based on the rule of thumb equation for spacing between skylights, the spacing was calculated to be Rule of thumb: The Distance between skylights (on center) is given by: = <1.4 ceiling height + 2 x splay width + skylight width = 1.4 x x Distance between skylights with splay (on center) = < 25.4 ft The following figure gives one layout options for skylight spacing layout for this condition Figure 58: Spacing layout of light well with splay HESCHONG MAHONE GROUP 57

17 Condition 2: Skylight without splay Rule of thumb: The Distance between skylights (on center) is given by: = <1.4 ceiling height + 2 x splay width + skylight width = 1.4 x Distance between skylights without splay (on center) = < 19.4 ft The following figure give some options for skylight spacing layout for this condition. Here, the skylights are sized 4 x4 and 14 apart but are 12 in number, with a SFR of 4.4%. In order to maintain the same SFR of 3.3%, the skylight size would have to be reduced to 4 x3 dimensions. Figure 59: Layout without splay, 12 skylights ( 3 x 4 ) with SFR 3.3% Design Development Stage 5: Refining Design At this stage, it is important to finalize the following based on the schematic design: Finalize the skylight dimensions, number and spacing 4 x4 skylight opening dimensions with 24 x 20 oc skylight spacing with splay (SFR 3.3%) was finalized for this example Coordinate the skylight spacing with spacing of electric light, sprinklers, and diffusers. Decide on photocontrol set points along with electric lighting layout to make maximum potential through skylighting Finalize the skylight glazing type Double glazing with clear prismatic lens was decided for this example. Decide on light control devices like adding louvers, reflectors or diffusers. In this example, the diffuser was added to the skylight design. HESCHONG MAHONE GROUP 58

18 Reserve space by putting up the skylight opening and well dimensions on the CAD drawings of roof and reflected ceiling plan Stage 6: Photometric Analysis The photometric analysis was done based for the following conditions of the design room: 1. Light well with splay clear sky conditions (4ft x 4ft skylt, 10 ft x 10 ft splay, total ht. 6 ft, 9 in number) 2. Light well with splay cloudy sky conditions (4ft x 4ft skylt, 10 ft x 10 ft splay, total ht. 6 ft, 9 in number) 3. Light well without splay clear sky conditions (4ft x 4ft, total ht. 3 ft, 9 in number) 4. Light well without splay clear sky conditions (4ft x 4ft, total ht. 3 ft, 16 in number) Light well with splay clear sky conditions The results of this design on a clear day were acceptable with at least 63% of room 50 footcandles or more. The space had reasonable uniformity with the average light level 77fc, about 1.5 times design light level (50 fc), which is ideal for glazing with no selective transmitting characteristics. The skylights selected for this design are probably too large. An analysis under peak solar conditions is expected to produce marginally excessive hot spots. More skylight smaller in size would be more appropriate at this ceiling height. Light well with splay cloudy sky conditions For a cloudy day, the average light level was about 10 fc, max 20 fc, calling for about 80% of design power of electric light systems. Light levels can be increased dramatically by using more skylights. Peak conditions need to be managed by combination of louvers and glazing performance. Clear day Cloudy day Figure 60: Photometric results for light well with splay (clear and cloudy conditions) Light well without splay clear sky conditions (4ft x 4ft, total ht. 3 ft, 9 in number) The results of this design were marginally acceptable. The skylight transmission had to be reduced to 24% to have similar results with other case (light well with splay). Skylight selected are too large. Smaller skylights with higher transmission would give equal or better results at this ceiling height. HESCHONG MAHONE GROUP 59

19 Light well without splay clear sky conditions (4ft x 4ft, total ht. 3 ft, 16 in number) Here, the number of skylights were increased from 9 to 16. Results were acceptable and the skylight transmission had to be reduced by 56% to have similar results with light well with splay. The size of skylight still needs to be reduced further to give better results. Clear day Cloudy day Figure 61: Photometric results for light well without splay (clear and cloudy conditions) Conclusion of photometric analysis The splay allows for fewer skylights for this room condition. Skylights can be spread larger and either be physically larger or higher transmission and provide equal daylight distribution and uniformity to a larger number of skylights of the same size without splay. Component Specifications Scope of Work 1. Contractor should provide all materials and labor necessary to install the whole skylight well system, including the unit skylight, throat, splay, diffusers, component interconnectors and other structural supports required to attach skylight well to the structure. 2. Other works related to skylight well installation includes: electrical, and fire protection, and suspended ceiling system. Quality Assurance 1. Contractor or manufacturer should provide documentation of product evaluation reports, such as those issued by International Code Council Evaluation Services (ICC-ES) or Underwriters Laboratory (UL) listing. 2. Contractor or manufacturer should provide product performance evaluation reports, such as photometric reports. 3. Contractor should submit a sample of the product to be installed for owner approval. Materials Skylight 1. Skylight frame should be self-flashing, insulated and have an integrated condensation gutter. HESCHONG MAHONE GROUP 60

20 Throat Splay 2. Skylight frames should have a load-carrying capacity of. 3. Glazing should be double-glazed acrylic dome classified as CC2 material. Thickness should be a minimum of. 4. Opening should be fitted with burglar bars, or fall protection bars. 5. Glazing material should have a minimum haze of 90%. 1. Throat material to be of metallic fabric with reflectivity of at least 80%. 2. Material should have cut-outs for sprinkler head penetration. 3. Interconnectors should be of a non-corrosive metal material. 4. Connector of lightwell to structure should allow for isolated movements of the lightwell independent from the structure. 1. Splay material should be thick white-painted gypsum board, with reflectivity of at least 80%. 2. Connectors should be made of a non-corrosive metal material, properly concealed and finished on the lightwell interior. 3. Throat-splay connector should have attachments for a diffuser. Light Control Devices 1. Diffuser should be prismatic acrylic lens with a light transmittance of at least 80%. 2. Diffuser should have a haze value of at least 90%. 3. Diffuser attachment should be openable, allowing access to the lightwell. Suspended Ceiling Systems 1. Ceiling system should have attachments to the splay. Fabrication 1. Finish, fabricate and shop prepare all assemblies under the responsibility of one manufacturer. 2. Allow thermal movement of materials when subject to a temperature differential from -30 F to 180 F. Installation 1. Worker should be protected during installation according to OSHA Skylights should be installed according to the National Roofing Contractors Association (NRCA) Roofing and Waterproofing Manual. 3. Installation should be coordinated with installers of related systems, such as suspended ceiling, fire protection, electrical, mechanical and structural. 4. Installation procedure should be compliance with seismic requirements. 5. Throat and splay should be installed according to manufacturer s installation instructions. HESCHONG MAHONE GROUP 61

21 6. Lightwell space should be reserved during construction to prevent the trespass of other building services. HESCHONG MAHONE GROUP 62

22 References American Institute of Architects AIA CAD Layer Guidelines. American Institute of Architects. ANSI S Acoustical Performance Criteria, Design Requirements and Guidelines for Schools. Archoustics West. Achieving Effective Office Acoustics. Accessed from the World Wide Web: Brook, Martha California Electricity Outlook: Commercial Building Systems. Presentation at PIER Buildings Program HVAC Diagnostics Meeting, Oakland, CA on April 16. Ching, Francis D.K Building Construction Illustrated, 2 nd Ed. New York: Van Nostrand Reinhold. Coldham Architects Beauty, Productivity, Energy Savings. Accessed from the World Wide Web: Cooper, Kenneth. November 26, Study Says Natural Classroom Lighting Can Aid Achievement. Washington Post. Page A14. Designlights Consortium KnowHow. Lexington, Massachusetts: Northeast Energy Efficiency Partnerships, Inc. Accessed from the World Wide Web: Energy Information Administration (EIA) Commercial Buildings Energy Consumption Survey: Building Characteristics Table. Accessed from the World Wide Web: Heschong Mahone Group, Inc Integrated Design of T-bar Ceilings with Skylight Wells. Access through the World Wide Web: Heschong Mahone Group, (HMG) Skylighting and Retail Sales, Pacific Gas & Electric, Heschong Mahone Group Skylighting Guidelines. Irwindale, Calfiornia: Southern California Edison. ICC Evaluation Service, Inc AC 16: Acceptance Criteria for Plastic Skylights. Whittier, California: ICC Evaluation Service, Inc. ICC Evaluation Service, Inc AC 17: Acceptance Criteria for Sloped Glass Glazing in Solariums, Patio Covers and Prefabricated Skylights. Whittier, California: ICC Evaluation Service, Inc. ICC Evaluation Service, Inc Acceptance Criteria 79: Acceptance Criteria for Skylights with Plastic Frames. Whittier, California: ICC Evaluation Service, Inc. HESCHONG MAHONE GROUP 63

23 ICC Evaluation Service, Inc. AC85: Test Reports and Product Sampling. Whittier, California: ICC Evaluation Service, Inc. ICC Evaluation Service, Inc Rules of Procedure for Evaluation Reports. Whittier, California: ICC Evaluation Service, Inc. New Buildings Institute, Inc Advanced Lighting Guidelines. White Salon, Washington: New Buildings Institute, Inc. Can be accessed from the World Wide Web: Nittler, Ken and Mattinson, Bill Proposed 2005 Title 24 Standards. Presentation at the Annual CABEC Conference in Tahoe, Nevada on May 16, Norris, Davidson, and Tillett, Linnaea Daylight and Productivity: Is there a Causal Link? Glass Processing Days Conference Accessed from the World Wide Web: PG&E Daylighting Initiative: Retail Applications Ralph s Grocery. Accessed from the World Wide Web: nated.pdf. Romm, Joseph, and Browning, William Greening the Building and the Bottom Line. Snowmass, Colorado: Rocky Mountain Institute. Thayer, Burke Miller Daylighting and Productivity at Lockheed. Presentation. Accessed from the World Wide Web: Thor, Leifur Artifacts. Accessed from the World Wide Web: Warner, Jeffrey Sizing Up Skylights. Home Energy Magazine. Accessed from the World Wide Web: WindowandDoor.net Material Supply May be Tight According to Panel at WDMA Tucson Meeting. Accessed from the World Wide Web: HESCHONG MAHONE GROUP 64

24 Coefficient of Utilization Glossary The Coefficient of Utilization is an indication of a fixture's efficiency. In other words, just how well the fixture gets the lamp lumens onto the horizontal surface to be lit. It is expressed as a percentage of the total light produced by the lamp. Effective Aperture Effective aperture is a measure of light transmitting ability of a fenestration system. It is a product of the skylight-to-floor ration (SFR), the visible transmittance (Tvis) and the well factor. Value ranges from 0 to 1.0, with most practical skylights at less than 0.1. Isolux / Isofootcandle Contour An isolux contour is a line graph of a space showing equivalent illuminance values in lux or footcandles. Luminance Luminance is the amount of visible light leaving a point on a surface in a given direction. This "surface" can be a physical surface or an imaginary plane, and the light leaving the surface can be due to reflection, transmission, and/or emission. Photocontrol Photocontrol is a lighting control system that adjust the electric lighting power in response to the amount of interior light or ambient daylight available. Photometrics Photometrics, a description of the magnitude and direction of light distribution from a source, is the basis of predicting how that light source shall light a space. Photometry It is the science of measuring visible light in units that are weighted according to the sensitivity of the human eye. Plenum Plenum is the space between the suspended ceiling and the floor or roof above. A plenum may also be under a raised floor. Prescriptive Measure Non-residential buildings can comply with the Energy Code by using either of two approaches: prescriptive or performance approach. Prescriptive measures become the base case upon which buildings that use the performance method will be compared against. Skylight-to-Floor Ratio (SFR) HESCHONG MAHONE GROUP 65

25 SFR is the ratio of the gross skylight opening area to the daylit floor area. Solar Heat Gain Coefficient (SHGC) SHGC is the fraction of solar radiation admitted through a glazing assembly. It is the sum of the transmitted solar energy plus that portion of the absorbed solar energy which flows inward. It measures how well a product blocks heat caused by sunlight. It is expressed as a number between 0 and 1. The lower the number, the less heat is transmitted. Uniformity Uniformity refers to the even distribution of light levels in a space. It is a factor of daylight diffusion and skylight spacing. Visible Transmittance Visible transmittance is the fraction of light energy that enters a particular glazing material or skylight assembly over the visible portion of the solar spectrum. Well Cavity Ratio (WCR) The well cavity ratio is a parameter used to determine the light well factor. It is a measure of the geometric shape of the well. Well Factor (WF) The well factor is the ratio of the amount of visible light leaving the skylight well to the amount of visible light entering the skylight. HESCHONG MAHONE GROUP 66

26 Appendix APPENDIX 1: ACRONYMS BOCA Building Officials and Code Administrators International CBECS Commercial Building Energy Consumption Survey CEC California Energy Commission ICBO International Conference of Building Officials ICC International Code Council ICC-ES International Code Council Evaluation Service NBI New Buildings Institute PG&E Pacific Gas and Electric Company PIER Public Interest Energy Research SBCCI Southern Building Code Congress International SFR Square Foot Ratio (see Glossary for definition) SHGC Solar Heat Gain Coefficient (see Glossary for definition) TAG Technical Advisory Group UBC Uniform Building Code WE Well efficiency (see Glossary for definition) WF Well factor (see Glossary for definition) HESCHONG MAHONE GROUP i

27 APPENDIX 2: NATIONAL CONSTRUCTION VOLUME Building Activity 1990 to 1999 (in M sq. ft.) Annual Construction (in M sq. ft.) Education 1, Mercantile 2, Office 1, Food Sales Food Service Q Q Health Care Lodging Public Assembly Public Order and Safety Religious Worship Service Warehouse and Storage 2, Other Vacant Q Q TOTAL 11,094 1,109 Annual construction for educational, retail (mercantile) and office spaces is million sq ft. This is equivalent to 46% of the total annual construction volume. See figure below for percentages. Warehouse and Storage 19% Other 3% Education 12% Religious Worship 3% Public Order andsafety 2% Service 3% Public Assembly 7% Loding 7% Food Sales 3% Health Care 4% Office 17% Mercantile 20% HESCHONG MAHONE GROUP ii

28 APPENDIX 3: MARKET POTENTIAL FOR SUSPENDED CEILING SYSTEMS IN SPLAY APPLICATIONS Assumptions Building Occupancy: Retail Application Floor Area / Ceiling Area: 40,000 sq ft Square Foot Ration (SFR): 4% Skylight Size: 4 x 4 = 16 sq ft Splay Angle: 45 Well Opening Size: 12 x 12 = 144 sq ft Calculations How many skylights do we need? At 4% SFR, 40,000 sq ft * 0.04 = 1,600 sq ft of skylight area 1,600 sq ft of skylight area / 16 sq ft = 100 skylights 144 sq ft of ceiling opening * 100 skylights = 14,400 sq ft What is the area of splays in the building? Area per splay = (4 x 5.66 ) * 2 = sq ft Splay Area per skylight = sq ft * 4 splays = sq ft per skylight Total Splay Area in building = sq ft * 100 skylights = 18,112 sq ft Summary Total Ceiling Area with suspended ceiling installations = 25,600 sq ft Total Area of Installation lost due to skylights = 14,400 sq ft = 36% of bldg area Total Area of Splay Installation = 18,112 sq ft = 45% of bldg area HESCHONG MAHONE GROUP iii

29 APPENDIX 4: SKYLIGHT SIZING CHART The chart below compares the number of skylights required as a function of splay sizes, and angles. The sample below assumes the following conditions: SFR 4% Skylight size 2 x 4 The chart above indicates that for skylights of the same dimensions, splayed wells would Ceiling Height Splay Angle Skylight Dimension Ceiling Opening Dimension Skylight Spacing Spacing other direction Relative # skylights x 4 2 x % x 3 6 x % x 4 6 x % x 5 8 x % x 6 12 x % x 3 6 x % x 4 6 x % x 4 9 x % x 6 12 x % x 4 3 x % x 5 6 x % x 4 8 x % x 5 8 x % x 6 12 x % x 5 6 x % x 4 8 x % x 5 10 x % x 6 12 x % x 4 4 x % x 5 8 x % x 6 8 x % x 5 10 x % x 8 12 x % x 5 8 x % x 6 8 x % x 5 10 x % x 8 12 x % require less skylight installations than an unsplayed one. For splayed skylights, skylights with wider and higher splays will also require less skylights. HESCHONG MAHONE GROUP iv

30 APPENDIX 5: CODE REQUIREMENTS Plastic Skylights UBC Section IBC Section IRC Section R UBC Sections 2409 and 2603 IBC Sections 2405 and 2609 ANSI Standard Z Aluminum Design Manual, October 1994 Glass Skylights UBC Chapter 34 For IBC compliance, fasteners in contact with aluminum shall be in accordance with the Aluminum Design Manual Section of Part 1-A or 1-B. For UBC compliance, fasteners in contact with aluminum shall be in accordance with Sections and Plastic material should comply with UBC Section 217 or IBC Section For UBC compliance, fasteners in contact with aluminum shall be in accordance with Sections Labeling in accordance with UBC Section 5402 UBC Section 2311 for wind uplift load Glass thickness to comply with UBC 54-1, Table No Glass and glazing strength should be designed according to the 2001 California Building Code Section 2409 Sloped Glazing and Skylights - Design Loads. Acrylic plastic glazing should be compliant with the 2001 California Building Code Section Plastics Skylights. The proper installation of gypsum board constructed throats should be according to the 2001 California Building Code Section 2511A Gypsum Wallboard. Code requirement for plastic diffusers includes the 2001 California Building Standards Section on Plastic applications in Light Diffusing Systems. HESCHONG MAHONE GROUP v

31 APPENDIX 6: APPLICABLE TESTS Plastic Skylights The following tests are required as per Acceptance Criteria 16 of the International Code Council Evaluation Services: ASTM D 618 Method for Conditioning Plastics and Electrical Insulating Materials ASTM D 635 Test Method for Rate of Burning and/or Extent and Time of Burning of Self-supporting Plastics in a Horizontal Position ASTM D 638 Test Method for Tensile Properties of Plastics ASTM D 790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials ASTM D 1929 Test Method for Ignition Properties of Plastics ASTM D 2565 Practice for Operating Xenon Arc-Type Light Exposure Apparatus With and Without Water for Exposure of Plastics ASTM D 2843 Test Method for Density of Smoke from the Burning or Decomposition of Plastics ASTM E 84 Standard Test Method for Surface Burning Characteristics of Building Materials ASTM E 108 Standard Test Method for Fire Tests of Roof Coverings ASTM E 330 Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights and Curtain Walls by Uniform Static Air Pressure Difference. ASTM E 331 Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference UL 790 Test Method for Fire Resistance of Roof Covering Materials Glass Skylights The following tests are required as per Acceptance Criteria 17 of the International Code Council Evaluation Services: If insulating glass glazing is used, it should comply with ASTM E774 Specification for Sealed Insulating Glass with a minimum Class C rating when tested in accordance with ASTM E 773 Test Method for Seal Durability of Sealed Insulating Glass Units Load tests to be in compliance with ASTM E330Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights and Curtain Walls by Uniform Static Air Pressure Difference. No water infiltration into the interior should occur when tested in accordance with ASTM E331 Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference and AAMA Standard The Methods of Test for Metal Curtain Walls. HESCHONG MAHONE GROUP vi

32 Skylights with Plastic Frames The following tests are required as per Acceptance Criteria 79 of the International Code Council Evaluation Services: ASTM D Standard Test Method for Determining Ignition Temperature of Plastics ASTM D Standard Test Method for Rate of Burning and/or Extent and Time of Burning of Plastics in a Horizontal Position ASTM D 4226 Standard Test Methods for Impact Resistance of Rigid Poly(Vinyl Chloride) (PVC) Building Products ASTM D 638 Standard Test Method for Tensile Properties of Plastics Only one of the following weathering tests need to be applied: o ASTM D 1499 Standard Practice Filtered Open-Flame Carbon-Arc Type Exposures of Plastics o ASTM D 2565 Standard Practice for Xenon Arc Exposure of Plastics Intended for Outdoor Applications o ASTM D 4364 Standard Practice for Performing Outdoor Accelerated Weathering Tests of Plastics Using Concentrated Sunlight o ASTM D 1435 Standard Practice for Outdoor Weathering of Plastics o ASTM D 4329 Standard Practice for Fluorescent UV Exposure of Plastics Miscellaneous Tests These tests are not required by the ICC-ES, but would be beneficial for testing the performance of skylight systems: Fire-rating requirements of materials should have a flame-spread index of 25 or better (Class A) when tested according to ASTM E84 Standard Test Method for Surface Burning Characteristics of Building Materials. Air infiltration of the skylight unit should be tested in accordance with ASTM E283 Air leakage Through Exterior Windows, Curtain Walls and Door under Specified Pressure Differences Across the Specimen. Gypsum board material strength should be compliant with ASTM C472 Test Methods for Physical Testing of Gypsum, Gypsum Plasters, and Gypsum Concrete. Joints between gypsum boards should be compliant with ASTM C Standard Test Methods for Joint Treatment Materials for Gypsum Board. Installation of gypsum board materials should be in accordance with ASTM C Standard Specification for Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Wood Studs or Steel Studs and ASTM C475 Specification for Joint Compound and Joint Tape for Finishing Gypsum Board. Suspended ceiling systems should be rated Class-A when tested according to ASTM E84 Standard Test Method for Surface Burning Characteristics of Building Materials and ANSI/UL 263 ASTM E119 and NFPA 251 Fire-Resistance Rating of a Ceiling Assembly for t-bar ceiling systems. Framing members for ceiling panels should comply with ASTM C Standard Specification for Nonstructural Steel Framing Members while attachments should comply HESCHONG MAHONE GROUP vii

33 with ASTM C Standard Specification for Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products. HESCHONG MAHONE GROUP viii

34 APPENDIX 7: WELL ASSEMBLY SCHEDULE Commercial building types that are being targeted by this document have a variety of ownership/occupant and construction types. These factors affect the construction schedule. Recommendations for efficient construction schedules for buildings with skylight wells are discussed for four of the most common conditions below. Condition A: Owner-occupied New Construction Option 1 1. Roof framing and the roof opening, including supplemental framing for the opening, are constructed at the same time. 2. A curb for the skylight is constructed on top of the opening and coordinated with the roof decking. 3. A cricket at the uphill side of the curb is constructed to direct water flow on the roof to the sides and around the skylight curbs. 4. The roofing insulation, where applicable, is installed over the deck. 5. The roofing membrane is installed over the deck with appropriate flashing on the curb. 6. The skylight is installed atop the roof curb. 7. Throat material is attached onto the curb, including supplemental support and bracing system for the throat. 8. Attach markers to block out space for future splay installations. 9. Building systems, such as the mechanical, plumbing, and sprinkler piping, etc. are installed. 10. The splay material and its associated supports are installed. 11. The suspension grid for the ceiling is attached to the splay opening and ceiling supports, followed by placing ceiling panels. 12. Diffuser is installed, if applicable. 13. Electric light fixtures are put in place. Condition B: Owner-Occupied New Construction Option 2 In some skylight designs, the splay may be used as a transitional component for adjusting light well location or splay opening. In such cases, the construction schedule should be as follows: 1. Initial construction scheduling is as Steps 1 to 9 in Option The suspended ceiling system will be installed according to designed ceiling pattern. 3. The light well splay and its associated supports are installed to adapt to the positions of the throat and ceiling opening. 4. Diffuser is installed, if applicable. 5. Electric light fixtures are placed finally. HESCHONG MAHONE GROUP ix