DD and Code Flashcards
Fire resistance codes
come from ASTM, UL & NFPA, IBC too
occupancy type determines what rating each bldg element gets, but 1:structure, 2:ext wall, esp if load-bearing, 3:floors, 4:roofs, 5:interior, nonloadbearing partitions
Dampers
Fire dampers, fusible (heat makes them drop closed) or sensor controlled
Smoke dampers, same but for smoke, in lower rated assemblies
Types of fire-rated walls
fire partition = 1-hr rated wall assembly (unless in lower occupancy class/sprinklere, then 30 min), w 20 min doors in corridors, 45 min doors elsewhere
required in exit corridors, elev lobbys, between units in multioccupancy R, C and hotels
fire barrier = more protection, intended to enclose fire, 1-hr rated or more, always goes to underside of structure, w 45 min to 3-hr doors, openings and/or glazing area limited
required in enclosed exit stairs, exit passages, occupancy separations, fire separations, etc.
- fire wall* = separates construction types (allowable area game), 2-4-hr rated, go from foundation to roof, must have structural separation
- smoke barrier* = membrane, 1-hr rated, that prevents smoke passage, openings are 20 min rated
Finishes and flame spread
restricted to certain areas, occupancy groups, sprinklering, according to surface burning characteristics
applies to wall and ceiling panels, not trim, frames, or thick/cemented panels
class A-C (resistant to less) flame spread index
textile finshes are measured by critical radiant flux (a kind of flame spread) Class I (more resistant), Class II (less)
decorative fabrics can’t add too much burnable material, max heat release, flame spread
Occupancy types
assembly, business, educational, factory/industrial, hazardous, institutional (hospitals, jails, group homes, daycares), mercantile/commerical, residential, storage, utility
if a storage area within another occupancy is less than 100 sq ft, it is considered part of the parent occupancy class
accessory occupancy = a less than 10% of rest of bldg different occupancy doesn’t require fire separation, except at live/work units (all the same occupancy), dwelling/sleeping units still require separation, hazardous occupancies always required separation
incidental uses = adjacent, smaller, but poses greater risk than main occupancy type, must be separated by a fire barrier, sprinklered, cannot exceed 10% of main area (eg furnace rm, machine rm, paint shops, laundry rms, battery rms, waste storage rms)
Construction types
I (fire-resistive)
II (non-combustible)
III (ordinary)
IV (heavy timber)
V (wood frame)
Allowable height and floor area
depends on occupancy, construction type, whether sprinklered, how close to property lines/public frontage, etc.
if at least 25% of bldg fronts a public way of 20ft+ measured at a right angle, then allowable area increases, by allowable area factor
occupant load factor: max allowable area per occupant, by use type
Mixed occupancies
max allowable ht and area are based on most restrictive occupancy group
ratio of total areas of occupancy types must equal 1
occupancies must be separated by fire wall/area separation wall, to make separate fire areas (mostly)
each occupancy must comply w bldg ht limitations based on the type of construction
hazardous occ, sleeping unit, accessory occupanices, non-separated ocupancies have additional restrictions
Means of egress
continuous, unobstructed path of vertical and horizontal egress travel from any point in bldg to public way (not private land, w unobstructed area from ground to sky, clear width at least 10’ wide)
exit access (start, is not protected, but may be fire rated, is the part where distance is regulated), exit (path, protected, fully enclosed, 1-2 hr rated), exit discharge (still on property, out of the bldg, can be lobby)
Occupant load
calculated by actual number, pretty much only used when there are fixed seats to count
calculated by table, lists of occupancy types tell you how many ppl are allowed based on square footage, by ‘occupant load factor’ or are presumed to be occupied by one person, based on iether gross floor area (support services too) or net floor area (space actually used by occupant)
calculated by combination, when accessory space exits through primary space, loads are added together, determines only min. widths of egress, not number of exits
Required number of exits
must have more than one exit if goes over certain limits found in IBC table (area, exit distances, sprinklers)
some exceptions: individual R2 dwelling units, max 20, sprinklered, care suites w egress otherwise met (all in one or two story bldgs only, except if R2 has only 4 units, small area, can have basement plus three floors)
3 required when 501-1000 occupants
4 when 1000+
Common path of travel
exit access travel distance: based on occupancy, sprinklers
have to count the protected exit path, too; distance is to exit of bldg
from a table
Separation of exits
if two exits required, must be separated by not less than half the total diagonal dimension of building/area served (one third, if sprinklered)
3rd/4th exit must be ‘reasonable distance’ apart
must be located in obvious places
Exit widths
ADA governs anyway, usually (32”/36” min), but calculated at .2” per person
if more than 50 occupants, 44”
two or more exits, width is such that loss of any one exit would not reduce the remaining capacity to less than 50% of total required
Exiting through other spaces
usually not allowed, but can happen if:
one of the two rooms is an accessory
neither room is H occupancy
there is a discernable path of egress travel to an exit
can never pass through kitchens, storerooms, closets, or similar, and no locked rooms that prevent free movement
Exit corridors
fully enclosed, protected, limited choices for paths of travel
if two exits exist, they must both be accessible so that if one is blocked, the other remains free
often must be fire-rated (usually fire partition) unless group E where at least half leads directly to exterior/ground level, group R inside units, parking garages, group B where only one exit is required
minimum widths: 24”-96” depending on occupancy (36” most common), but also by multiplying olf. If over 50 occupants, not less than 44”
can only be encroached upon by doors swings, up to 1/2 of corridor when swinging, but at fully open, not more than 7”
by handrails, but no more than 4.5”
by nonstructural horizontal projections (decoration, trim) by 1.5”
structural elements, between 27”-80” AFF no more than 4”
openings in 1-hr rated must be 20-min rated, w draft and smoke seals, have closer, have UL label, glazing only w approved fire rated, no more than 25% of wall area usu
all ducts must have fire dampers, 20-min rated
can only stop being protected if goes through foyers, lobbies, reception rooms that are fire rated the same, or in sprinklered group B at enclosed elevator lobbies
dead ends not allowed, in that if two exits are required, must be able to get to other exit in corridor, except ok if less than 20 ft, 50 ft sprinklered, in jails, or if length is less than 2.5 times its width at narrowest
Exit doors
cannot be disguised in any way, even if ‘extra’
minimum 32” clear, max 48”, min 80” high, with exceptions
must be hinged or pivot, with exceptions (collapsible revolving)
must swing in the direction of travel, but not swing into a path of travel (recess the door when it does this, watch push side clearance), max opening force of 5 lbf at interior, 15 lbf elsewhere
be UL rated, fire rating attached to adj wall rating, have smoke seal and pass positive pressure test
special arrangemetns for power-operated, gates, threshold ht, etc.
Exit stair
stair is the steps themselves, stairway is the stairs to get from one floor to the next
interior exit stairway: meets egress requirements for protected path (completely enclosed); exit access stairway gets you to protected path
basements count, mezzanines don’t
all must be 44” wide if more than 50 occupants (.2” per occupant), never less than 36” wide (ADA wants 48” clear, so usu governs), handrails no more than 4.5” projection, not into clear space
treads btwn 4”-7”, risers not less than 11”, but ADA can’t exceed 7”, have acceptable nosing (must project out)
max distance btwn landing is 12’ vertical, landings must be width of stair, but need not be more than 48” if straight run
handrails required, even if one riser, both sides unless residential, greater than 5’ width needs intermediate rail, unless: decks, patios, walkways, at entry single steps, at changes in room elevations in side dwellings
4+ stories: 2-hr rating (90 min doors), less than 4: 1-hr rating (1 hr doors)
exceptions: if only two stories, doesn’t have to be inclosed except when group I
part of a single residency
if floor opening does not connect more than 4 stories, is sprinklered, floor opening not greater than twice the stair projection, protected by draft curtain
Exit handrails
mounted between 34”-38”
meet graspability requirements (finger recess if not roundish)
1.5” away from wall
must terminate in wall, floor or post
must extend 12” past top riser, tread (+ 12” for ADA) at bottom one
High rise construction
anything over 75’ from ground
auto sprinklers, smoke detectors and alarms, communication systems, central control station for firefighters, smoke control at exit stairs, standby power systems (and more)
Guardrails required at
open-sided walking surfaces, mezzanines, platforms, stairs, ramps more than 30” AFF
but not stages and certain other platforms
must be 42” min high, no larger than 4” sphere passes through openings up to 36” ht., then 4 3/8” ok
resist loads of 50 lbf/ft in any direction applied at top of rail
except in some residential places, but are required in some residential operable windows, also can’t have operable windows below 36” that can open more than 4” if more than 72” from ground
FAR
gross floor area:area of lot
bulk plane restriction
angled line from edge of lot, allow view, air to adj properties
