height more than 750mm 1m minimum 1m (+/- 10mm)
Stair without string
1m (+/- 10mm)
Stair with string
String
Not acceptable
Not acceptable
Ø100mm min
Ø100mm min
Ø100mm min Ø100mm min
3.3.16.2 Handrail grip size.
The handgrip portion of handrails shall have a cross section of 32mm minimum to 65mm maximum. Other handrail shapes, which provide an equivalent grasping surface, are permissible.
Edges shall have a minimum radius of 3mm.
3.3.17 Guards
3.3.17.1 Guards required.
Porches, balconies or raised floor surfaces located more than 750mm above the floor or grade below shall have guards not less than 1.00m in height. Open sides of stairs with a total rise of more than 750mm above the floor or grade below shall have guards not less than 1.00m in height measured vertically from the nosing of the treads.
See Figure A3-10 Guards
3.3.17.2 Guard rail-opening limitations.
Required guards on open sides of stairways, raised floor areas, balconies and porches shall have intermediate rails or ornamental closures which do not allow passage of a sphere 100mm or more in diameter. Required guards shall not be constructed with horizontal rails or other ornamental pattern that results in a ladder effect.
3.3.18 Foam plastic 3.3.18.1 General.
The provisions of this section shall state the requirements and uses of foam plastic as insulation, structural filling or decoration
3.3.18.2 Foam characteristics 3.3.18.2.1 Internal characteristics
The minimum density shall be more than 3 kN/m3. 3.3.18.2.2 Surface burning characteristics.
All foam plastic or foam plastic cores in manufactured assemblies used in building construction shall have a flame-spread rating of not more than 75 and shall have a smoke-developed rating of not more than 450 when tested for the maximum thickness intended for use in accordance with ASTM E 84.
3.3.18.3 Foam protection
All foam shall be protected from inside and outside by appropriated barrier to prevent damage from.
1- Vapour (humidity from hot air migrating from the hot side to the cold side of the wall, in this region from outside to inside)
2- Fire (both sides)
3- Rodent (rats, mice, etc.) 4- Termites
3.3.18.3.1 Thermal barrier
Foam plastic shall be separated from the exterior of the building by minimum vapour barrier as follows:
Polythene 0.150 mm thick (included in the wall complex)
or metallic cladding (corrosion resistant sheet of 0.50 mm minimum) or 25mm thickness of masonry or concrete
3.3.18.3.2 Fire barrier
To allow a minimal ignition protection of 15minutes a fire barrier shall be used as follows:
3.3.18.3.2.1 From outside
Metallic cladding (corrosion resistant sheet of 0.50 mm minimum) or 25mm thickness of masonry or concrete
or 20mm structural wood or 25mm particleboard.
3.3.18.3.2.2 From inside Metallic cladding
or 25mm thickness of masonry or concrete or 20mm structural wood
or 25mm particle board
or 13mm gypsum board (the gypsum board shall be installed using a mechanical fastening system to ensure that the gypsum board will remain in place when exposed to fire).
3.3.18.3.3 Rodent damage (rats, mice, etc.)
All foam shall be externally protected against any destruction by rodents. This applies to the edge of the foam.
3.3.18.3.4 Termite damage.
The use of foam plastics in areas of termite infestation shall be in accordance with this code.
3.3.18.4 Specific requirements.
3.3.18.4.1 Foam-filled doors.
Foam-filled doors are exempt from the requirements of this Section.
3.3.18.4.2 Interior trim.
Foam plastic trim defined as picture moulds, chair rails, baseboards, handrails, ceiling beams, door trim and window trim may be installed, provided that:
1. The minimum density is 3.50kN/m3,
2. The maximum thickness of the trim is 13mm and the maximum width is 100mm, The trim constitutes no more than 10 percent of the area of any wall or ceiling, and
The flame-spread rating does not exceed 75 when tested per ASTM E 84. The smoke-developed rating is not limited.
3.3.19 Flame spread and smoke density 3.3.19.1 Wall and ceiling.
Wall and ceiling finishes shall have a flame-spread classification of not greater than 200.
3.3.19.2 Smoke developed index.
Wall and ceiling finishes shall have a smoke developed index of not greater than 450.
3.3.19.3 Testing.
Tests shall be made in accordance with ASTM E 84.
3.3.20 Insulation 3.3.20.1 Insulation.
Insulation materials, including facings, such as vapour barriers or breather papers installed within floor-ceiling assemblies, roof-ceiling assemblies, wall assemblies, crawl spaces and attics shall have a flame-spread index not to exceed 25 with an accompanying smoke developed index not to exceed 450 when tested in accordance with ASTM E 84.
3.3.20.2 Loose-fill insulation.
Loose-fill insulation materials, which cannot be, mounted in the ASTM E 84 apparatus without a screen or artificial supports shall have a flame-spread rating not to exceed 25 with an accompanying smoke-developed factor not to exceed 450 when tested in accordance with CAN/ULC-SI02-M88.
3.3.20.3 Cellulose loose-fill insulation.
Cellulose loose-fill insulation shall comply with CPSC 16-CFR, Parts 1209 and 1404. Each package of such insulating material shall be clearly labelled in accordance with CPSC 16-CFR, Parts 1209 and 1404.
3.3.20.4 Exposed attic insulation.
All exposed insulation materials installed on attic floors shall have a critical radiant flux not less than 1200 watt/m2.
3.3.20.5 Testing.
Tests for critical radiant flux shall be made in accordance with ASTM E 970.
3.3.21 Dwelling unit separation 3.3.21.1 Multi-family dwellings.
Dwelling units in multi-family dwellings shall be separated from each other by wall and/or floor assemblies of not less than 1 hour fire-resistive rating when tested in accordance with ASTM E 119.
Fire-resistive-rated floor-ceiling and wall assemblies shall extend to and be tight against the exterior wall, and wall assemblies shall extend to the underside of the roof sheathing.
3.3.21.1.1 Supporting construction.
When floor assemblies are required to be fire-resistive, the supporting construction of such assemblies shall have an equal or greater fire-resistive rating.
3.3.21.2 Townhouses.
Each townhouse shall be considered a separate building and separated by walls for exterior walls.
A common 2-hour fire resistive wall is permitted for townhouses if such walls do not contain plumbing or mechanical equipment, ducts or vents in the cavity of the common wall.
Electrical installations shall be installed in accordance with TTS 26 20 505 Electrical code.
Penetrations of electrical outlet boxes shall be in accordance with this code.
3.3.21.2.1 Continuity.
The common wall for townhouses shall be continuous from the foundation to the underside of the roof sheathing, deck or slab and shall extend the full length of the common wall.
3.3.21.2.2 Parapets.
Where parapets are to be provided for townhouses as an extension of the common wall in accordance with the following:
Where roof surfaces adjacent to the wall are at the same elevation, the parapet shall extend not less than 800mm above the roof surfaces.
Where roof surfaces adjacent to the wall are at different elevations and the higher roof is not more than 800 mm above the lower roof, the parapet shall extend not less than 800mm above the lower roof surface.
3.3.21.2.3 Structural independence.
Each individual townhouse shall be structurally independent.
3.3.21.3 Exceptions:
Foundations supporting common walls.
Structural roof and wall covering sheathing from each unit may fasten to the common wall framing.
Non structural wall coverings.
Flashing at termination of roof covering over common wall.
Townhouses separated by a common two-hour fire-resistive wall.
3.3.21.4 Sound transmission.
Wall and floor-ceiling assemblies separating dwelling units shall provide airborne sound insulation for walls and both airborne and impact sound insulation for floor-ceiling assemblies.
3.3.21.4.1 Airborne sound.
Airborne sound insulation for wall and floor-ceiling assemblies shall meet a Sound Transmission Class (STC) of 45 when tested in accordance with ASTM E 90.
3.3.21.4.2 Structural-borne sound.
Floor/ceiling assemblies between dwelling units or between a dwelling unit and a public or service area within a structure shall have an impact insulation class ( IIC ) rating of not less than 45 when tested in accordance with ASTM E492.
3.3.21.5 Rated penetrations.
Penetrations of wall or floor/ceiling assemblies are required to be fire resistant or should be protected in accordance with this section.
3.3.21.5.1 Through penetrations.
Through penetrations of fire resistance rated wall or floor assemblies shall comply with this section.
Exception: Where the penetrating items are steel, ferrous or copper pipes or steel conduits, the annular space shall be permitted to be protected as follows:
1 In concrete or masonry wall or floor assemblies where the penetrating items is a maximum of 150mm nominal diameter and the opening is a maximum of 90 000mm2, concrete, grout or mortar shall be permitted where installed in the full thickness of the wall or floor assemblies.
2 The material used to fill the annular space shall prevent the passage of flame and hot gases at the location of the penetration for the time period equivalent to the fire resistance rating of the construction.
3.3.21.5.1.1 Fire resistance rated assembly.
Penetrations shall be installed as tested in the approved fire resistance rated assembly.
3.3.21.5.1.2 Penetration fire-stop system.
Penetrations shall be protected by an approved penetration fire-stop system installed as tested in accordance with ASTM E814, with a minimum positive pressure differential of 0.25mm of water (3 Pa) and shall have an F rating of not less than the required fire resistance rating of the wall or floor /ceiling assembly penetrated.
3.3.21.5.2 Membrane penetrations.
Where walls are required to have a minimum 1hour fire-resistance rating, recessed light fixtures shall be so installed such that the required fire resistance will not be reduced.
3.3.21.6 Non-rated penetrations.
Penetrations of horizontal assemblies without a required fire resistance rating shall comply with this section.
3.3.21.6.1 Non combustible penetrating items.
Non combustible penetrating items that connect not more than three stories are permitted provided that the annular space is filled with an approved non-combustible material or approved penetration fire-stop system.
3.3.21.6.2 Combustible penetrating items.
Combustible penetrating items that connect not more than two stories are permitted provided that the annular space is filled with an approved material to resist the free passage of flame and the products of combustion.
3.3.22 Moisture vapour retarders 3.3.22.1 Moisture control.
In all framed walls, floors and roof/ceilings comprising elements of the building thermal envelope, an approved vapour retarder having a maximum rating of 1.0 perm, when tested in accordance with ASTM E96-92, (Standard Test Methods for Water Vapour Transmission of Materials), shall be installed on the warm side of the insulation.
3.3.23 Protection against decay 3.3.23.1 Location required.
In areas subject to decay damage the following locations shall require the use of an approved species and grade of lumber, pressure preservatively treated, or decay-resistant.
See Table C1 Timber names for use in Trinidad & Tobago.
Wood joists or the bottom of a wood structural floor when closer than 450mm or wood girders when closer than 300mm to exposed ground in crawl spaces or un-excavated area located within the periphery of the building foundation.
All sills or plates, which rest on concrete or masonry exterior walls and are less than 200mm from exposed ground.
Sills and sleepers on a concrete or masonry slab, which is in direct contact with the ground unless, separated from such slab by an impervious moisture barrier.
The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 15mm on tops, sides and ends.
Wood siding, sheathing and wall framing on the exterior of a building have a clearance of less than 150mm from the ground.
Wood structural members supporting moisture-permeable floors or roofs which are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier.
Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapour retarder is applied between the wall and the furring strips or framing members.