U factor should not be converted to r factor, since r is usually only used with insulation, and u factor is used with nonhomogeneous assemblies e. While other factors including concrete compressive strength, the thickness and quality of the. Calculators for structural engineers, construction professionals and steel building specifiers. Concrete floor slab flatness and levelness stovers. Slabongrade heat loss estimation hvacr engineering. Background information on design theories is followed. One of two classes for floors in contact with ground. Building additions that include a slab on grade construction also are subject to the slab edge requirements listed in the ieccirc. Aci 360, design of slabs on grade, refers to this as a type b slab. Many of the simplifications and enhancements developed for comcheck have provided the technical basis for code changes submitted to the international code council icc. Reported by committee 302 american concrete institute. Heated slabsongrade will feature hot water pipes or coils embedded within or beneath the slab to provide space heating. Ada241 567 algorithms for slabongrade heat transfer.
F numbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab. Design of slabs onground reported by aci committee 360 aci 360r06 this document presents information on the design of slabs onground, primarily industrial floors. A reasonable rvalue for a normal concrete slab can be estimated using an rvalue, the thermal resistance per inch of thickness, between 0. A reasonable rvalue for a normal concrete slab can be estimated using an rvalue, the thermal resistance per. The minimum thermal resistance rvalue of the insulation around the perimeter of unheated or heated slab on grade floors shall be as specified in table c402. The perimeter heat loss factor for slab on grade floors formula in book heated slab slab on grade construction in which the heating elements, hydronic tubing, or hot air distribution system is in contact with, or placed within or under, the slab. Ffactor blog dietary tips to increase fiber intake. The wire reinforcing institute recommends the use of the subgrade drag theory for slabs up to 150 feet in length.
Department of energy under contract deac0576rl01830 technical support document for version 3. Cracks in concrete floors or slabs occur in poured concrete slabs may be found both in basement and in slab on grade or patio home construction and have a variety of causes and cures that we discuss here as we explain how to repair cracked concrete floors and as we describe slab on grade construction or patio home construction cracks and as. The second set of values for unheated and heated slabs should be for vertical insulation, not horizontal. For slab subjected to concentrated post loading for k 100 pci per pca slab thickness design for industrial concrete floors on grade figure 7b, page 10. In climate zones 4 and 5, the code requires certain slabs below grade slabs that are less than 12 in.
Calculating the impact of ground contact on residential. A heated slab is a type of construction that has a slab on grade concrete floor with a heating system embedded in or beneath the slab floor. It addresses the planning, design, and detailing of slabs. So you could try using an edge r of zero and a floor u based on 6inch thick concrete and see what result you get. Ground heat transfer calculations using c and f factor. They had a berber carpet over cheap pad, but they like to walk around the house barefoot and the floor feels cold to their feet, esp. Heat losses from heated slabs are greater than that of unheated slabs because the temperature is warmer. The u factor for concrete slabs concrete construction. Floor slabs on grade structural engineering general.
They are calculated using the standards set forth in astm e1155, which is the standard test method for determining f f floor flatness and f l floor levelness numbers. Ffactors are provided for both heated and unheated slabs. Since fill will need to be imported into the house footprint to bring the grade up to the underside of the slab, floors that will be high off the ground are not logical candidates for a slab. The fallacy of the straightedge method was the location of the measurement. In contrast to the ufactor for floors, the ffactor for slabongrade floors is expressed per linear foot of building perimeter. Slab insulation do i understand the code requirements. Slab on grade ffactor for a large building leeduser. Concrete floor slab flatness and levelness traditionally allowable tolerances of concrete floor slabs were determined by checking the slab surface with a 10 foot straightedge.
Client has a family room that was slab on grade with nothing between the concrete and dirt. Generally speaking, lower density concrete provides better insulation than higher density concrete. Minneapolis slab floor with various insulation treatments 41 sevennode network model 45 14 undisturbed ground temperature profile 50 15 finite difference model of two square slabs 54 16 tleat fluxminneapolis, mn 58. Help us do more ffactor hopes you, your family and friends are healthy and safe during these uncertain times. Area of the facade, including overhanging soffits, cornices, and protruding columns, measured in elevation in a vertical plane parallel to the plane of the face of the building. How to specify, order and use welded wire reinforcement tf 202r03. Guide to design of slabs onground reported by aci committee 360 aci 360r10 this guide presents information on the design of slabs onground, primarily industrial floors. Supports are needed for longterm performance of welded wire reinforcement in slab on grade tf 702r08 wri tech facts. Your 12 inches of r5 horizontal insulation has an ffactor of 0. Concrete strength, f c 4000 psi instructions for use of figure 3. The ufactor for concrete slabs concrete construction. Common tolerances were 18 inch or 14 inch in 10 feet. Reading the fine print i realized that the army manual is using a safety factor of 5.
Department of energy doe and pacific northwest national laboratory pnnl intend to refine and enhance the comcheck materials over time in response to needs expressed by users. Unheated slabongrade floors are all other floors in contact with ground. Concrete slab on grade thickness analysis for slab. Stresses in floor slabs on grade resulting from vehicular loads are a function of.
The u factor for any building component is the inverse of its rvalue, a more familiar term describing thermal resistance or insulation. Building thermal envelope opaque assemblies intended to comply on an assembly u, c or f factor basis shall have a u, c or f factor not greater than that specified in table c402. A new method for designing floor slabs on grade due to the. Heavy loads in building s such as warehouses include moving load s, stationary live loads, and wall loads.
Guide for concrete floor and slab construction aci 302. How to reinforce concrete slab on ground to control cracking. What would you recommend to warm up the floor, esp, something that doesnt. Tm 580912 concrete floor slabs on grade subjected to. Figure 2 typical node pattern used for basement evaluation.
The report addresses the planning, design, and detailing of slabs. The pca and wri slab on grade design methods for industrial floors led to a design for concrete fatigue, even though 2. Matching these slabongrade construction layersinsulation will mean youre achieving the target ffactor for your perimeter zones. Heated slabongrade floors include all floors that are heated directly in order to provide heating to the space. The american concrete institute indicates acceptable ranges for flatness and levelness in aci 302.
The insulation shall be placed on the outside of the foundation or on the inside of the foundation wall. Online concrete slab on grade analysis calculator for slab subjected to interior concentrated post or wheel loading assuming slab is reinforced for shrinkage and temperature only. Comparing the values found in this table with the values found in table 11 in designing floor slabs on grade there is a huge disparity. Depending on where the measurement was made, the slab may pass or fail the specified. Clarifying slabongrade insulation in ashrae standard 90. Assembly u factor, c factor or f factorbased method.
Aci committees 360, design of slabs on ground, and 302, construction of concrete floors, have been at the forefront of the effort to provide the industry with the tools to produce slabs that are flat and level, with a densely finished surface, stable joints, and limited cracking while being capable of supporting applied loads. Theoretical concepts, practi cal applications, basis of. I dont consider it to be a fully insulated slab since the horizontal insulation only extends 24 inwards, and a6. Figure 1 typical node pattern used in slab on grade evaluation. Commercial buildings or portions of commercial buildings enclosing group r occupancies shall use the u, c or f factor from the group r column of table c402. Concrete slab on grade analysis calculator for post or. Best fix for cold slabongrade family room floor fine. Slab thickness is the greatest single factor controlling the loadcarry capacity of a slab onground. A concrete slab on grade works well on relatively level sites with a first floor or basement level that will be relatively close to existing grade. Background information on design theories is followed by discussion. Our mission has always been to support health through nutrition. Per pca slab thickness design for industrial concrete floors on grade figure 3, page 5 job name. Algorithms for slab on grade heat transfer calculations by. Calculating the inverse of that, 1r, would give you a u factor in the range of 1.
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