Professional Engineers Ontario West Toronto Chapter. Maziyar Bolour, P. Eng.

Transcription

1 Professional Engineers Ontario West Toronto Chapter Maziyar Bolour, P. Eng. Slide 1 of 45

2 Learning Objectives At the end of this presentation, participants will be able to: describe an ICF and its components, identifying how these contribute to a durable, safe, energy-efficient, and sustainable construction project; list the financial, environmental, and sustainable benefits of ICF construction and how ICFs can contribute to LEED points earned on a building project; explain how involving engineers and architects early in the design process contributes to a safe, structurally sound, costefficient building project, and describe the ICF installation process, including two critical elements of field installation. Slide 2 of 45

3 History Developed in Europe following World War II (1940s) as an inexpensive way of replacing damaged buildings First patent registered in Switzerland in the 1940s which used insulation made of treated wood fibres and cement Plastic foams developed in 1950s, allowing Canadian to register first patent in 1966 (by a Canadian named Werner Gregori) for forms resembling modern ICF The first U.S. patent was issued for ICFs in 1971 Slide 3 of 45

4 Introduction ICF is a system of formwork for reinforced concrete that stays in place as a permanent interior and exterior substrate for walls, floors, and roofs Could be made of hollow, light-weight blocks/panels/planks that lock together Exterior walls of the form may be composed of: Expanded Polystyrene (EPS) Cement-bonded wood fibre Cellular concrete Interior consists of steel bars, plastic or metal cross-ties Forms also serve as thermal insulation Slide 4 of 45

5 What Are ICFs? Pre-assembled forms/blocks are generally manufactured using rigid insulation panels (EPS) held together by high-impact polypropylene webs/cross-ties. It combines insulating effectiveness of EPS with thermal mass and structural strength of a reinforced concrete wall Reduce energy consumption Fast, and easy construction Slide 5 of 45

6 Types of ICFs Unit Shape and Assembly ICF wall can be assembled from different unit shapes (Pre-assembled Blocks or Independent Panels) Slide 6 of 45

7 Types of ICFs Concrete Shape Concrete can take different shapes within wall Most Common Slide 7 of 45

8 Components Reinforced Concrete Core 4", 6", 8", 10", or 12" thick 2,500 to 4,000 psi (20 MPa to 30 MPa) 5 to 6" slump ¾ or ⅜" aggregate Steel bars: Grade 400W or 400R (400 MPa) Insulating Concrete Form (ICF) Units Forming Capacity (865 lbs/ft Slide 8 of 45

9 Specialty Forms Tapered top Corner reversible block Radius form 45 reversible block Additional built-in internal reinforcement Slide 9 of 45

10 Design Wind Load: ICFs vs. CMUs ICF 8" core 3000 psi concrete 12" o.c. CMU 8" 1500 psi Concrete 12" o.c. CMUs ICFs Slide 10 of 45

11 STC: Sound Transmission Control ICF STC over 50 (ICF rating is based on ½" drywall interior veneer; equivalent exterior attached creates a barrier that virtually eliminates outside noise) WOOD STC 37 STC Wood ICFs Slide 11 of 45

12 The Bottom Line ICFs incorporate all of the following into one product: substrate for acrylic stucco furring strips for drywall and exterior structural non-combustible wall assembly with appropriate exterior finish sound attenuation vapour barrier air barrier chase for utilities insulation closed cell R-22 or R-30 (wall assembly) Slide 12 of 45

13 Construction Schedules Slide 13 of 45

14 Construction Schedules Slide 14 of 45

15 What are the advantages of ICF homes? Significant energy savings: In a study by the Portland Cement Association, ICF homes saved up to 50% on heating and cooling costs over wood-framed homes. The poured concrete walls provide an excellent thermal mass, which helps maintain an even indoor air temperature. This also allows you to spend less on a smaller HVAC system. Severe weather resistance: Concrete houses have survived tornadoes and hurricanes in areas where wood houses were flattened. When they are properly engineered, they should also withstand earthquakes. Texas Tech University conducted a study to determine the suitability of ICFs for above-ground storm shelters, wood stud missiles fired under tornado conditions were unable to penetrate ICFs. Slide 15 of 45

16 Advantages of ICF homes - Continued Significantly lower insurance premiums: Insurance premiums can be up to 50% less with ICF homes, especially in areas where severe weather (hurricanes, tornadoes, etc.) is common. Faster construction time: ICF construction eliminates several steps as compared to wood construction (such as sheathing and insulating exterior walls) Insect resistant: In many areas of the country, termites are a major problem. There is nothing for termites to eat in an ICF house. Significant exterior noise reduction: Studies have shown that about only one-third of exterior noise penetrates an ICF wall as compared to a wood-framed house. Slide 16 of 45

17 Construction Costs With ICF systems: building materials are lightweight dramatic reduction in compensation claims and crane time required no winter heat required; no tarps required no severe falls most lifts are 8 to 12' on the interior side of building typical crew one licensed carpenter, three laborers Slide 17 of 45

18 Absorption Capabilities ICFs are ideal for: Post-disaster structures defense and military compounds Staged Blast Slide 18 of 45

19 Reduced Air Infiltration air infiltration reduced to negligible levels extreme filtration levels of intake air are attainable airtight buildings should use ground-air heat exchange system reduces amount of additional energy required to heat and cool lowers the relative humidity small amount of electrical power operates air intake fan Slide 19 of 45

20 LEED (USGBC) Contribution Points (2009) ICF CONTRIBUTION IN LEED FOR HOMES Credit Total Points Available Potential Benefit Potential ICF Contribution ID2.1m ID2.2: Durability Required element ICF products contribute strongly towards durable buildings EA1: Energy Performance 34 points ICF structures can achieve enhanced energy performance of 32 to 44% Meets requirement points MR2: Environmentally Preferable Products 8 points ICF block can be constructed with locally sourced recycled content in the concrete MR3: Waste Management 3 points Concrete used in ICFs can be recycled or reused on site 1 point 1 point Total 45 points points ICF CONTRIBUTION IN LEED 2009 FOR NEW CONSTRUCTION & MAJOR RENOVATIONS (NC) EAc1: Energy Performance MRc2: Waste Management 19 points CF structures can achieve enhanced energy performance of 32 to 44% 2 points Concrete used in ICFs can be recycled or reused on site MRc4 Recycled Content 2 points Recycled content is counted in LEED by a cost fraction that is weighted by mass MRc5 Regional Materials 2 points ICF block can be constructed with locally sourced concrete points 1 point 1 point 1 point Total 25 points points Note: ICFs will also contribute to the same categories in CaGBC LEED certification programs. Slide 20 of 45

21 Starting a Commercial ICF Project work closely with the ICF manufacturer representative involve an engineer from the very beginning have a licensed architect on board (must understand how to design with ICFs ) have the proper field training efficient ICF installation is critical to project success Slide 21 of 45

22 Engineering steel placement is critical within ICFs polypropylene web over-design is not desirable quickly determine ICF concrete core size detail and submit lintels with plans proactive engineering discovers potential challenges concrete mix design should address consolidation, forming capacity, seasonal temperatures, etc. Slide 22 of 45

23 Design Parameters and Standards residential construction: steel may be placed as per the OBC or the prescriptive tables published by NRC-CCMC (ICF Manufacturer) Consider the limitations of Part 9 of the OBC/NBCC Custom ICF Homes- Mostly designed by a structural engineer commercial construction: concrete, steel size, spacing, splicing, and placement should be determined by a structural engineer ICF Wall/floor design must comply with the provincial building code and fire safety standards for structural adequacy and serviceability NBCC, OBC (Limit State Design Method) Concrete CAN/CSA A23.1, CAN/CSA A23.2, CAN/CSA A23.3 Carbon Steel Bars for Concrete: CAN/CSA G30.18 ICF: CAN/ULC S717.1 (Standard for Flat Wall Insulating Concrete Form Units) Slide 23 of 45

24 Curtain Wall / Structural Load Bearing Wall Curtain Wall Structural Load Bearing Wall Slide 24 of 45

25 Architectural Considerations The details are critical: vertical floor-to-ceiling heights (divisible by ICF s height?) window and door placement within wall assembly pay attention to connections at floor and roof Fastening detail for exterior materials floors should have detailed sections manufacturer s representative should meet with design professionals at onset of project Slide 25 of 45

26 Ten-Step Installation Overview 1. Outline walls 2. Place corner blocks first / Install horizontal reinforcing steel and lap splicing 3. Install second course of ICF 4. Install window and door bucks 5. Continue installing block courses Slide 26 of 45

27 Ten-Step Installation Overview 6. Install alignment/bracing around the wall perimeter 7. Install vertical reinforcing steel after top course 8. Pour concrete in lifts of 3 to 4 ft (0.9 to1.2m) 9. Wet set anchor bolts in top course of upper floor Slide 27 of 45

28 Initial Considerations Forms should be level and webs aligned Check levels after two courses Correct dowel placement dependent on design/codes Planning is critical Slide 28 of 45

29 Field Installation select and/or train ICF crew typical ICF crew four to five workers large commercial projects often two crews may require makeshift, light forklifts to move material material should be dropped in the center of project on each floor, leaving room for bracing crews need to work as team rather than independently work on the ground for as long as possible Slide 29 of 45

30 Critical Elements Slide 30 of 45

31 Consolidation proper internal consolidation eliminates voids use a pencil head vibrator use ICFs designed to withstand proper internal vibration good mix design makes for a very good ICF core Slide 31 of 45

32 Bracing provides safe work platform aligns walls paramount to good ICF construction Slide 32 of 45

33 Bracing Inadequate Bracing Proper Bracing Slide 33 of 45

34 Buck Selection and Type selection of buck material critical to commercial ICF construction speed material can be wood, vinyl, or steel good buck design and assembly speed up commercial construction Section of vinyl window sill buck Collapsible, reusable window buck Curved window buck Slide 34 of 45

35 Concrete Pumping ICFs are pumped 99% of time review safety procedures prior to concrete placement mix design can be critical typically one pump charge per floor Slide 35 of 45

36 Utilities 2.5" or 3.25" tolerance (foam) becomes the chase for electrical or plumbing most cuts done with electric chain saw and hot knives special electrical boxes available for ICF installation Slide 36 of 45

37 Below Grade Water Protection Dimple Board Peel and Stick System Slide 37 of 45

38 Floor Type with ICFs several floor options are available residential construction typically floor systems hung on inside walls commercial construction floors directly bear on ICF walls type of floor is typically dependent on the span plank or core slab most popular in commercial ICF construction insulated (concrete/foam/steel) floor (or roof) can improve the STC rating and thermal performamce Slide 38 of 45

39 Insulated Floor Slide 39 of 45

40 Insulated Floor Installation Overview Insulated floor and roof system Stacking the floor and roof system Pouring concrete onto the assembled forms Smoothing concrete to create a flat surface Slide 40 of 45

41 ICF Project Applications Gymnasium Condominium Complex Drury Inn Tim Hortons Slide 41 of 45

42 ICF Project Applications Hospitality Sector Best Western Educational Facility Slide 42 of 45

43 Fire Station Rebuild Slide 43 of 45

44 Traditional Construction: Challenges Faced construction time required for existing system construction is highly dependent on weather required lifts on exterior for application of: sheathing, insulation, waterproofing, EIFS quality of walls dependent on tradesmen leaking during construction protection of interior finishes multiple inspections windows and walls may leak after completion potential for mold and mildew growth with hollow wall assemblies Slide 44 of 45

45 Traditional Construction: Methods and Obstacles Slide 45 of 45

46 The ICF Solution quicker construction time all types of weather less damage during construction highly durable consistent, standardized, high-quality walls essentially foolproof airtight building envelope higher energy efficiency than traditional construction methods sound barrier improved resistance to mold and mildew growth flexibility in exterior design long term building solution low maintenance improved job site safety over other methods sustainable product Slide 46 of 45

47 The ICF Solution Lower Levels Closed In Fast Construction Slide 47 of 45

48 Construction Cost Assessment Upfront cost comparison: for same size - 108,000 sq.ft., 180-room building initial material cost increased by only 11% Cost savings: less drywall damage = 6% savings heating during construction = 2% savings job site safety costs = 3.5% savings Results: net initial savings of 0.5% plus reduced operation/energy costs, lower maintenance costs (sustainable construction) Slide 48 of 45

49 In Summary ICFs reduce construction time and labor costs ICFs reduce sound transmission ICFs produce a very energy-efficient structure ICFs protect the environment by reducing harmful emissions by 30 50% ICFs ensure maximum safety: walls have fire rating of 3+ hours resistance to high winds prevent insect damage and mold and mildew growth Slide 49 of 45

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