DD and Code

Question 1

Fire resistance codes

Answer 1

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

Question 2

Dampers

Answer 2

Fire dampers, fusible (heat makes them drop closed) or sensor controlled

Smoke dampers, same but for smoke, in lower rated assemblies

Question 3

Types of fire-rated walls

Answer 3

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

Question 4

Finishes and flame spread

Answer 4

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

Question 5

Occupancy types

Answer 5

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)

Question 6

Construction types

Answer 6

I (fire-resistive)

II (non-combustible)

III (ordinary)

IV (heavy timber)

V (wood frame)

Question 7

Allowable height and floor area

Answer 7

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

Question 8

Mixed occupancies

Answer 8

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

Question 9

Means of egress

Answer 9

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)

Question 10

Occupant load

Answer 10

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

Question 11

Required number of exits

Answer 11

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+

Question 12

Common path of travel

Answer 12

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

Question 13

Separation of exits

Answer 13

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

Question 14

Exit widths

Answer 14

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

Question 15

Exiting through other spaces

Answer 15

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

Question 16

Exit corridors

Answer 16

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

Question 17

Exit doors

Answer 17

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.

Question 18

Exit stair

Answer 18

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

Question 19

Exit handrails

Answer 19

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

Question 20

High rise construction

Answer 20

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)

Question 21

Guardrails required at

Answer 21

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

Question 22

FAR

Answer 22

gross floor area:area of lot

Question 23

bulk plane restriction

Answer 23

angled line from edge of lot, allow view, air to adj properties