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Public Safety & Special Construction — ICC B1 Practice Questions

84 questions · 17% of the ICC B1 exam

Worked questions

1. The window meets the required net clear opening area and both clear dimensions. The finished sill of the openable portion sits 46 inches above the floor, and the grille is fastened with screws that require a screwdriver to remove. What should the inspector cite?

  • AOnly the grille, because the sill height limit is waived once the opening delivers the full 5.7 square feet of required clear area

    Clear opening area and sill height are independent requirements, and meeting one does not excuse the other. A window can pass the 5.7-square-foot test and still sit too high for a child or a firefighter to use it.

  • BNothing, because an escape opening on the first floor is exempt from the sill height limit and from the release requirements

    Emergency escape openings are required in every sleeping room regardless of story, and no floor level is exempt from these two rules. A grade-floor opening earns a reduced area allowance, not a waiver of height or operation.

  • Both the sill height and the grille, because the sill is above the maximum height and the grille cannot be released without a tool
  • DOnly the sill height, because a grille of any form is acceptable so long as the clear opening behind it has been verified as adequate

    Bars, grilles and covers are permitted, but the code requires them to release from inside without a key, a tool or special knowledge. Verifying the opening area behind the grille says nothing about whether the grille itself opens.

Why C is correct

The maximum sill height for an emergency escape and rescue opening is 44 inches above the finished floor, measured to the sill of the openable portion, and this window is at 46 inches. The grille is a second, independent violation, because anything covering the opening has to release from inside without keys, tools, special knowledge or unusual force. Both items go on the correction notice.

What this question is testing

The item tests whether the candidate evaluates an escape opening against all of its requirements rather than stopping at the area calculation, and whether the candidate knows the release standard for coverings.

On the job

Owners add grilles after the final inspection far more often than during construction, which is why this shows up on complaint and rental inspections rather than on new work. When it does appear during a permitted remodel, the argument is always the same, that the screws come out fast. They do not come out fast in smoke at three in the morning by a child. Quick-release hardware that satisfies the rule is inexpensive and readily available, so there is no reason to negotiate.

Memory technique

Forty-four inches is about waist high on an adult, which is the tallest sill a child can still climb over.

Exam tip

An escape opening has four tests: area, width, height and sill. Anything covering it has a fifth: release without a tool.

Where to look it up

IRC Chapter 3, Section R310.2.2 for sill height and Section R310.4 for bars, grilles, covers and screens.

2. Measuring the flight, you find riser heights ranging from 7 inches to 7 and five-eighths inches, and tread depths ranging from 10 inches to 10 and one-quarter inches. No riser exceeds the maximum and no tread is below the minimum. What is the correct call?

  • AThe stairway passes, because every riser is under the 7 3/4-inch maximum and every tread meets the 10-inch minimum, which is all the code checks

    Maximum riser and minimum tread are only two of the three checks. The code adds a uniformity limit, and a flight can satisfy both dimensional limits while still varying enough between risers to trip a user.

  • The stairway fails, because the difference between the tallest and the shortest riser is greater than the three-eighths inch the code permits
  • CThe stairway fails, because the tread depths vary at all, and treads within a single flight are required to be identical with no tolerance

    The code allows a 3/8-inch tolerance precisely because field-built stairs never come out identical. Reading the rule as requiring zero variation would fail nearly every stair built, and it fails this one for the wrong reason.

  • DThe stairway passes, because the riser uniformity limit is written for stairways serving more than one story and not for a single flight

    Uniformity applies to every flight regardless of how many stories the stairway serves. The story count changes nothing in the stair geometry section; the misreading comes from mixing it in with the handrail continuity provisions.

Why B is correct

The code limits variation within a flight to three-eighths of an inch between the largest and smallest riser, and separately between the largest and smallest tread. Riser variation here is five-eighths of an inch, which exceeds the limit and fails. Tread variation is a quarter inch and passes. Compliance with the 7.75-inch maximum and the 10-inch minimum does not substitute for uniformity, because it is the change in rhythm that makes people fall.

What this question is testing

The item tests whether the candidate applies the uniformity limit independently of the maximum and minimum dimensions, and whether the candidate can identify which of two measured ranges actually exceeds the allowable variation.

On the job

Remodel stairs are where this lives. A contractor rebuilds a rotted bottom step or pours a new slab at the base, and the bottom riser ends up short or tall while the rest of the flight is untouched. The resulting trip happens on the way down, when the occupant has already established a stride. Measure every riser, not the first and last, and measure from nosing to nosing rather than from the framing, because carpet and treads change the finished dimension.

Memory technique

Three-eighths is about the thickness of a pencil. If you can feel the difference underfoot, it is too much.

Exam tip

Check three things on every flight: maximum riser, minimum tread and variation across the flight. Two of them can pass while the third fails.

Where to look it up

IRC Chapter 3, Section R311.7.5. The uniformity language sits with the riser and tread provisions themselves.

3. The foam is left exposed on the walls of what the plans show as a finished recreation room, and the contractor produces a report showing a flame spread index of 25 and a smoke-developed index of 300 for the product. What should the inspector require?

  • ANothing more, because flame spread and smoke indices in that range let the foam remain permanently exposed in a habitable space

    Those indices only qualify the foam as an acceptable material; they never let it stay exposed. The code requires a separation between foam plastic and the building interior no matter how favorably the material tests.

  • BThat a Class I vapor retarder be applied over the foam before finish work continues, since the foam face is the vapor control layer

    A vapor retarder is a moisture control layer, not a fire separation. Closed-cell foam at this thickness already retards vapor, and a sheet over it does nothing about the ignition and smoke hazard the code is addressing.

  • That an approved thermal barrier such as half-inch gypsum board be installed between the foam and the interior of the basement
  • DThat the foam be removed entirely, because spray-applied plastic foam may not be used on the interior of a foundation wall

    Foam plastic is expressly permitted on foundation walls; the code regulates how it is covered, not whether it may be used. Requiring removal treats a covering violation as if it were a material prohibition.

Why C is correct

Foam plastic must be separated from the building interior by an approved thermal barrier, and half-inch gypsum board is the reference assembly. Passing the 75 flame spread and 450 smoke limits qualifies the product for use but does not authorize leaving it exposed. Because this basement is a finished habitable room rather than an attic or crawl space entered only to service utilities, the reduced ignition barrier option is unavailable and gypsum board or an equivalent barrier is required.

What this question is testing

The item tests whether the candidate treats surface burning indices and the thermal barrier as separate requirements, and whether the candidate can identify when the reduced ignition barrier allowance for attics and crawl spaces applies.

On the job

Unfinished basements are the place this gets missed most, because the owner insulates now and finishes later, and the foam sits open for years. Inspectors also see it in attics and crawl spaces, where an ignition barrier is permitted instead, but only where the space is entered solely to service utilities and there is no storage. Once the owner puts boxes in that attic, the reduced barrier argument gets much weaker. Ask what the space will be used for, not only what it is called on the plan.

Memory technique

Half-inch gypsum is the yardstick. Anything else has to prove it performs as well.

Exam tip

Foam plastic questions usually hinge on covering it, not on testing it. Look for the thermal barrier.

Where to look it up

IRC Chapter 3, Section R316 for foam plastic, with R316.4 on the thermal barrier and R316.5 on the specific-use exceptions.

4. The window serving a first-floor bedroom is a grade floor opening. With the sash raised, the openable portion measures 30 inches wide by 24 inches high, and the framed rough opening for the unit measures 34 inches by 30 inches. The minimum net clear opening for a grade floor opening is 5.0 square feet, the minimum clear height is 24 inches and the minimum clear width is 20 inches. How should the inspector rule?

  • AThe clear height of 24 inches falls below the minimum, so a taller unit is required

    The measured clear height is 24 inches, which equals rather than falls below the minimum. Minimums are satisfied when the measurement lands exactly on the number.

  • BThe net clear opening is 5.0 square feet, which falls short of the 5.7 square feet required of every escape and rescue opening no matter where it is located

    The 5.7 square foot figure applies to escape and rescue openings other than those at the grade floor or below grade. Reading it as universal makes a compliant grade floor window look short.

  • The net clear opening is exactly 5.0 square feet and both clear dimensions are satisfied, so the window is acceptable
  • DThe opening measures 7.08 square feet, so it clears the requirement with room to spare

    Rough opening dimensions include the frame, the sash stiles and the sill. None of that is clear opening, and using it overstates the escape area by more than 40 percent here.

Why C is correct

Work the openable dimensions: 30 times 24 equals 720 square inches; 720 divided by 144 equals 5.0 square feet. The grade floor allowance is 5.0 square feet, so the area is met at the exact limit. Clear height equals the 24-inch floor and clear width comfortably beats the 20-inch floor. All three criteria are independent, and this unit satisfies each of them.

What this question is testing

The item tests three things at once: measuring net clear opening from the openable sash rather than the rough opening, knowing that the grade floor and below-grade allowance is 5.0 square feet, and treating area, clear height and clear width as three separate tests that must each be met.

On the job

Window suppliers publish clear opening data in their catalogs, and builders quote it at you on site. The inspector's job is to verify it with a tape through the actual raised sash, because a unit ordered right can still be installed with a stop screw, a shipping block or a factory limiter left in place. Grade floor openings are where the 5.0 square foot allowance saves a job, and where an inspector who insists on 5.7 across the board writes an unenforceable correction. Know which number belongs to which opening before you speak on site.

Memory technique

Five-seven for the upstairs, five-flat at grade.

Exam tip

Read the question for the words grade floor or below grade before you pick between 5.0 and 5.7 square feet.

Where to look it up

IRC Chapter 3, emergency escape and rescue openings, the opening area and dimension subsections.

5. The rear door leaf is 36 inches wide and it swings outward over the stoop. The stoop measures 34 inches from the face of the door out to its edge and 36 inches across. Applying the landing requirements for doors, how should the inspector rule?

  • AAcceptable: the landing only has to be as wide as the door it serves, and this one runs the full width of the leaf

    Width matching the door is the other half of the rule, not the whole of it. The landing also carries a minimum dimension in the direction of travel, and it can be plenty wide while still too shallow to stand on safely.

  • BAcceptable: a door that swings outward over an exterior stoop is exempt from the minimum landing dimensions

    Nothing exempts an outswinging door from landing dimensions. The swing direction only affects whether the landing may sit a step below the threshold, and the dimension applies to every required landing at a door.

  • CA violation: the landing must measure at least 48 inches in the direction of travel, leaving this one 14 inches short

    Forty-eight inches is not a residential landing dimension. The call is right but the number is not, which in the field means the contractor builds more than the code asks and the inspector loses credibility on the next item.

  • A violation: the landing must measure at least 36 inches in the direction of travel, and 34 inches falls short

Why D is correct

Run both checks. Width of landing 36 inches versus a 36-inch door leaf: satisfied. Depth in the direction of travel 34 inches versus a 36-inch minimum: two inches short, so a correction is required. The depth dimension exists so a person can stand clear of a swinging leaf without stepping off the edge.

What this question is testing

The item tests whether the candidate applies both landing dimensions rather than one, knows the 36-inch depth in the direction of travel, and rejects the idea that swing direction changes the dimensional requirements.

On the job

Rear and side stoops are poured by the flatwork crew from a rough sketch, often after the framer set the door, and 34 or 35 inches is what you get when someone forms to the width of a standard step form. Because the stoop is concrete, the correction is expensive and contentious, which is why experienced inspectors look at flatwork dimensions on the pre-pour visit rather than at final. Confirm the surface falls away from the door for drainage while you have the tape out.

Memory technique

Thirty-six deep, door-wide across.

Exam tip

Landing questions have two numbers: as wide as the door, and 36 inches deep.

Where to look it up

IRC Chapter 3, means of egress, the floors and landings at exterior doors subsection.

6. The fixed pane measures 30 inches wide by 60 inches tall. Its bottom edge is 22 inches above the landing surface at the base of the flight, and its nearest edge is 48 inches horizontally from the nosing of the bottom tread. The glass is ordinary annealed and there is no guard in front of it. The large-pane hazardous location criteria include a bottom edge less than 18 inches above the floor, and glazing at the bottom stairway landing is a hazardous location where it is less than 36 inches above the landing and within 60 inches horizontally of the bottom tread. How should the inspector rule?

  • AAcceptable: at 12.5 square feet the pane is well over the 9 square foot large-pane threshold, so a pane of that size is exempt from the stairway landing provisions in any case

    Size makes a pane a hazardous location; it never exempts one. The large-pane test also fails on its own here, because the bottom edge is 22 inches up and that rule needs an edge below 18 inches.

  • A violation: the glass sits 22 inches above the landing, under the 36-inch threshold, and 48 inches from the bottom tread, inside the 60-inch sweep, so safety glazing is required
  • CAcceptable: the pane sits a full 48 inches from the bottom tread, and the hazardous zone at a stairway landing reaches only 36 inches horizontally out from the nosing of that tread

    Thirty-six inches is the vertical figure in the landing rule, not the horizontal one. Swapping the two dimensions puts the glass outside a zone it is well inside of, at 48 inches against a 60-inch sweep.

  • DA violation, but it is corrected by applying an approved adhesive safety film over the face of the existing annealed pane in place of replacing the glass in the opening

    Applied film is not the safety glazing the code requires. The provisions call for glazing that meets the impact standard and carries a permanent identifying label, and film is a retrofit product with no standing here.

Why B is correct

Run both tests. Large pane: 12.5 square feet is over 9, but the bottom edge at 22 inches is above the 18-inch trigger, so the criteria are not all met. Bottom stairway landing: 22 inches is less than 36 inches above the landing, and 48 inches is within the 60-inch horizontal sweep from the bottom tread, so both conditions are met and the location is hazardous.

What this question is testing

This item tests whether the candidate evaluates a pane against every applicable hazardous location category rather than stopping at the first one, computes pane area correctly, and distinguishes the 60-inch sweep at a bottom landing from the 36-inch sweep alongside a stairway.

On the job

Windows at the foot of a stair are an architectural favorite and a genuine hazard, because a person falling down a flight arrives at that wall with real energy. Builders order the glass from a schedule that flags doors and tubs but rarely flags stair landings. Measure the two dimensions on site and check the corner of the pane for a permanent bug. If there is none, the glass is annealed no matter what the invoice says, and the correction is a replacement sash.

Memory technique

At the bottom of the stairs, sixty out and thirty-six up.

Exam tip

Glazing questions can trigger on more than one rule. Check every category before you clear a pane.

Where to look it up

IRC Chapter 3, glazing, the hazardous locations subsections covering large panes and glazing at stairways and landings.

7. The new basement door sits below the adjacent ground and is served by a sloped metal bulkhead enclosure, which the contractor is offering as the emergency escape and rescue opening. What must that bulkhead provide?

  • AA cover strong enough to carry a 40-pound-per-square-foot snow load, which is what qualifies it as an escape route

    Load capacity is a structural matter for the cover and says nothing about whether a person can get out. A strong lid that cannot be opened from below is worse than a weak one.

  • BA window well of at least 9 square feet at the foot of the stair, since a door alone cannot serve as an escape opening

    A code-complying door is one of the permitted forms of escape and rescue opening, so a window and its well are not required in addition. This option adds a requirement the code does not impose.

  • CA landing at the top of its steps and a guard on both sides, matching the requirements for an exterior stairway to grade

    Guards and landings belong to the stairway provisions and may apply to the steps themselves, but they are not what qualifies the bulkhead as the escape route. The releasing and clear opening conditions are.

  • Direct access from the basement to the yard, with clear dimensions letting the door open fully and operable without tools

Why D is correct

A bulkhead enclosure over an escape door has to give direct access from the basement to the yard, has to have clear opening dimensions that allow the door below it to be fully opened, and has to be operable from the inside without keys, tools or special knowledge. Those three conditions are what make the door count as the escape opening.

What this question is testing

Whether the candidate knows a door with a bulkhead can serve as an emergency escape and rescue opening, and can state the operational conditions the enclosure must meet rather than reaching for window well dimensions.

On the job

Basement finishes that add bedrooms are among the most common permits a residential inspector handles, and the escape opening is the item most often argued about. Bulkheads are attractive because the foundation already has a door. Inspectors open the bulkhead from inside with the lights off, swing the door to its stop, and check that a person could pass, since a bulkhead sized for a lawnmower often will not let the door swing.

Memory technique

Direct to the yard, door swings free, opens from below.

Exam tip

For a bulkhead, ask three things: does it reach the yard, does the door open fully, does it release from inside.

Where to look it up

IRC Chapter 3, emergency escape and rescue openings, the paragraphs covering escape doors and bulkhead enclosures.

8. The flight is 42 inches wide, and the landing at its foot measures 42 inches across and 34 inches in the direction of travel. What is the minimum depth required in the direction of travel, and does this landing comply?

  • 36 inches, so the landing is 2 inches short
  • B42 inches, so the landing is 8 inches short

    This applies the stair width in both directions. The width requirement governs the dimension across the landing, while the direction of travel has its own fixed minimum that does not scale with the flight.

  • C30 inches, so the landing complies as built

    Thirty inches is not a landing dimension in the stairway provisions, and adopting it would make the landing comply when it does not. The figure most often comes from confusing landings with other clearances.

  • D48 inches, so the landing is 14 inches short

    Forty-eight inches overstates the requirement. Using a number larger than the code sets is as much an error as using one too small, and it can force an unnecessary and expensive change.

Why A is correct

The landing dimension measured in the direction of travel is a flat 36 inches, while the dimension across the landing must equal the stair width. This landing is wide enough across at 42 inches but only 34 inches deep, so it falls 2 inches short of the 36-inch minimum.

What this question is testing

Whether the candidate can apply two different landing dimensions from two different rules at the same time, and does not let the stair width govern the direction of travel.

On the job

Landings get squeezed when a stair is moved during framing or when a hallway wall lands where the plan did not show it. Two inches sounds trivial, but a landing that shallow puts a person stepping off the bottom riser directly against a door or a wall. Inspectors measure both dimensions and note which rule each one comes from, because the correction differs: one may mean moving a wall, the other reframing the stair.

Memory technique

Wide as the stair, deep as three feet.

Exam tip

Across the landing, match the stair width. Along the direction of travel, 36 inches flat.

Where to look it up

IRC Chapter 3, stairways, the landings paragraph with its width and direction-of-travel dimensions.

9. The rail runs the full required length of the flight at the correct height, but at both ends it simply stops with an open, square-cut end projecting into the stairway. What does the code require at those ends?

  • ANothing; the requirement addresses the height and continuity of a rail, and the treatment of its ends is left to the builder

    The provisions address the ends specifically, and for a reason with an injury history behind it. Height and continuity are separate requirements that this rail happens to satisfy.

  • BThat each end be cut at an angle matching the slope of the flight, which keeps the projection out of the path of travel

    An angled cut is still an open end with a point on it. The requirement is that the end be closed off, whether by returning it to the surface behind or by terminating it in a post or terminal.

  • CThat the ends be capped with a rounded fitting and that the rail be extended 12 inches past the top and bottom risers

    The 12-inch extension belongs to accessible and commercial stairs under the building code, not to dwellings. Adding it here mixes two codes, and a rounded cap alone still leaves an open projecting end.

  • That the ends be returned to the wall or the guard, or terminate in newel posts or approved safety terminals

Why D is correct

Handrail ends have to be returned to the wall or the guard, or terminate in newel posts or approved safety terminals, so that an open end cannot catch clothing as a person steps off the flight. Any one of those terminations satisfies the requirement.

What this question is testing

Whether the candidate knows handrail end treatment is a distinct requirement with several permitted solutions, and separates the residential rule from the commercial extension requirement that looks similar.

On the job

Open rail ends are common on remodels and on stairs where the rail was installed by the homeowner. Inspectors look at both ends of every rail on the final, and the fix is a return fitting that costs a few dollars. Emergency departments see this injury regularly, usually as a fall taken by an older person whose sleeve or handbag caught the end while turning at the bottom of a flight.

Memory technique

No open ends: sleeves find them.

Exam tip

Return it, or land it in a newel or safety terminal. The 12-inch extension is a commercial rule.

Where to look it up

IRC Chapter 3, stairways, the handrail paragraph covering continuity and the treatment of ends.

10. The finished floor at the door is 27 inches above the walkway where the ramp will begin. Using the maximum slope the code allows for a ramp, what horizontal run does the sloped portion require?

  • 27 feet 0 inches
  • B22 feet 6 inches

    This is a 1 in 10 slope, which is steeper than the code allows and is not one of the recognized figures. It typically comes from rounding the required run down to fit the space available.

  • C18 feet 0 inches

    Eighteen feet corresponds to the 1 in 8 exception. That slope is permitted only where the building official finds the standard slope technically infeasible, and it is not the answer to what the code allows as a maximum.

  • D13 feet 6 inches

    Thirteen and a half feet is a 1 in 6 slope, which is far steeper than anything the ramp provisions allow and would be unusable by the person the ramp is being built for.

Why A is correct

At the maximum slope of 1 vertical in 12 horizontal, the run equals twelve times the rise: 27 inches times 12 is 324 inches, or 27 feet. Landings at the top and bottom are additional, so the contractor needs 27 feet of sloped run before the landings are placed.

What this question is testing

Whether the candidate can convert a rise into a required run at the maximum permitted slope, and distinguishes the code maximum from the steeper slope allowed only under a documented exception.

On the job

This conversation happens at the door with a tape, and the answer usually surprises the contractor: 27 feet of ramp will not fit in most front yards, which is why real ramps switch back with an intermediate landing. Inspectors who work the arithmetic on the spot save a demolition, because a ramp poured at 1 in 8 without a documented infeasibility finding comes out.

Memory technique

One in twelve: a foot of ramp for every inch of rise.

Exam tip

Run equals rise times 12. Do it in inches, then convert.

Where to look it up

IRC Chapter 3, ramps, the maximum slope paragraph and its exception.

11. The bottom exposed edge of the glass is 24 inches above the landing surface and the nearest edge of the glass is 40 inches horizontally from the bottom tread. A guard complying with the code stands between the landing and the window, and the plane of the glass is 24 inches back from that guard. The glass is annealed. What is the finding?

  • Not a hazardous location; a complying guard stands in front and the plane of the glass is over 18 inches behind it
  • BA hazardous location, because the glass is under 36 inches above the landing and within 60 inches of the bottom tread

    This is the correct reading of the two measurements and it stops one step short. The provision has an exception for glazing standing behind a complying guard, and that exception is what this arrangement satisfies.

  • CNot a hazardous location, because the bottom edge of the glass is more than 18 inches above the landing surface

    The 18-inch figure in this arrangement is the horizontal setback from the guard, not a height above the landing. Eighteen inches as a bottom-edge height belongs to the large-pane criteria instead.

  • DA hazardous location unless the guard in front of the glazing measures at least 42 inches above the landing surface

    Forty-two inches is the guard height used in commercial work. Residential guards are measured against a different figure, and in any case the exception turns on the guard complying and on the setback distance.

Why A is correct

The two measurements bring the glass into the provision, and the exception takes it back out. A guard complying with the code stands in front of it and the glass plane is 24 inches back, which is more than the 18 inches the exception requires, so the location is not hazardous on this ground.

What this question is testing

Whether the candidate applies the stairway landing criteria and then checks the guard exception, and measures the setback from the guard to the plane of the glass.

On the job

Half-wall guards with windows behind them are common in split-level and open-stair houses. Two things have to be confirmed before the exception is allowed: that the guard actually complies, in height and in opening limitation, and that the setback is measured from the guard to the plane of the glass rather than to the wall finish. Where the guard is short or the glass is close, the exception evaporates and the pane has to be tempered.

Memory technique

A complying guard 18 inches out keeps the glass out of reach.

Exam tip

Find the rule, then look for its exception. This one has a guard and an 18-inch setback.

Where to look it up

IRC Chapter 3, glazing, hazardous locations at stairways and landings, with its exceptions.

12. The opening is above grade, so it needs a net clear opening area of not less than 5.7 square feet, with a clear width of not less than 20 inches and a clear height of not less than 24 inches. The unit he is looking at will give a clear opening width of 34 inches. What is the least clear opening height that will satisfy the area requirement?

  • A20 inches, which is the smallest clear dimension the code states for an opening of this kind

    Twenty inches is the minimum clear width, not the minimum height, and it satisfies neither the height minimum nor the area. Mixing up which minimum goes with which dimension is the most common slip in this calculation.

  • B24 inches, which is the least clear height the code will accept in any escape opening

    Twenty-four inches meets the dimensional minimum and misses the area by about 5 square inches. That is exactly the trap: the two requirements are independent and both have to be met.

  • About 24 1/4 inches, since 5.7 square feet is 820.8 square inches and that over 34 is 24.14
  • DAbout 21 1/4 inches, working from the 5.0 square feet that applies to an opening of this kind

    Five square feet is the reduced area allowed at grade floor openings and below-grade openings served by a well. This bedroom is on the second floor, where the 5.7 square foot figure applies.

Why C is correct

Required area is 5.7 times 144, or 820.8 square inches. Divided by the 34-inch clear width, the clear height must be at least 24.14 inches, about 24 1/4. That also clears the 24-inch dimensional minimum, which by itself would leave the opening 4.8 square inches short on area.

What this question is testing

Whether the candidate converts area to square inches, solves for a missing dimension, and checks the result against the separate dimensional minimums instead of substituting one for the other.

On the job

Ordering the wrong sash is expensive because the rough opening is framed around it, so the arithmetic is worth doing at the counter rather than at final. The measurement is taken on the clear opening the sash actually leaves, which for a double-hung is roughly half the unit and for a casement is close to the full frame. Escape windows are the item most likely to be caught late and most likely to require framing to fix.

Memory technique

Twenty wide, twenty-four tall, and still 5.7 square feet to find.

Exam tip

Area and the two dimensional minimums are three separate tests. Run all three.

Where to look it up

IRC Chapter 3, emergency escape and rescue openings, minimum opening area and dimensions.

72 more in the bank

Answers and explanations for these are in the app.

  • The basement is reached by an interior stairway and the only exterior opening the contractor installed is a small hopper window in the mechanical closet. Which arrangement of emergency escape and rescue openings does the IRC require in this basement?
  • The single-hung sash slides up to leave an opening you measure at 20 inches wide by 38 inches high. The framed rough opening for the unit is 34 inches by 62 inches. What is the net clear opening area of this window and how should it be judged?
  • The well measures 30 inches of horizontal projection out from the foundation wall and 48 inches of width along the wall, and its floor sits 40 inches below the adjoining grade. Does the well comply, and on what basis?
  • The front entry is a pair of 30-inch sliding glass panels. The side entry is a side-hinged unit measuring 33 inches wide overall, with a clear width of 31.5 inches and a clear height of 79 inches when it is fully open. How should the inspector treat the required egress door for this dwelling?
  • The total rise from the lower finished floor to the upper finished floor is 112 inches, and the framer cut the stringers for 14 risers and 13 treads. What is the resulting riser height and how should the inspector rule?
  • Measured vertically from the sloped plane that touches the tread nosings up to the bottom of the duct, the clear height is 78 inches. The stairway width, the riser heights and the tread depths all comply. What is the correct call?
  • The stairway has six risers. A single wall-mounted handrail measures 30 inches above the nosing line, and it begins above the top riser but stops directly above the second riser from the bottom. What should the inspector require?
  • The cap measures five and one-half inches across and one and one-half inches thick, with lightly eased edges and no recess of any kind, and the builder says it is comfortable to hold. How should the inspector judge this graspable surface?
  • The ramp rises 21 inches from the walkway to the landing at the door, and the sloped portion measures 16 feet horizontally. What is the slope of this ramp and how should the inspector judge it?
  • The deck walking surface is 34 inches above the grade below. The builder installed a guard measuring 36 inches high with vertical balusters spaced so that a four and one-half inch sphere passes freely between them. What should the inspector do?
  • The two-by-ten ledger is fastened to the band joist of the house with 16d nails driven at an angle roughly every 8 inches, and the contractor points out that the nails are hot-dipped galvanized and that the joists are all hung properly. What is the correct call?
  • The ledger was fastened directly over the siding with correctly sized lag screws at the required spacing, and no flashing was installed at the top of the ledger. The builder says the lag screws carry the load and the siding above will shed the water. How should the inspector rule?
  • The joists bear on the ledger at the house and on a beam 12 feet away, then continue 4 feet past that beam to the outer edge of the deck. The span table the builder used permits the chosen joist size and spacing for the 12-foot span. What is the correct call?
  • The kraft facing is stapled to the faces of the rafters and hangs open to the room with no covering over it, and the contractor explains that the facing is the vapor retarder and has to face the living space. How should the inspector rule?
  • The electrician installed one smoke alarm in the upper hallway just outside the bedroom doors and one alarm on the main floor. What additional smoke alarms does the IRC require in this dwelling?
  • The dwelling has battery-only smoke alarms that are not interconnected, and the owner argues that the remodel does not touch the bedrooms and that the existing alarms were legal when the house was built. What does the IRC require before this permit can be finaled?
  • The builder installed no carbon monoxide alarms anywhere in the dwelling and states, correctly, that the house contains no fuel-burning appliance of any kind. What does the IRC require?
  • The fixed pane measures 34 inches wide by 76 inches tall. Its bottom edge is 8 inches above the finished floor, its top edge is 84 inches above the floor, and the room's walking surface runs right up to the glass. The glass carries no permanent marking of any kind. What should the inspector conclude?
  • The bottom edge of the glass sits 55 inches above the tub bottom that a bather stands on, and the glass is ordinary annealed. The builder points out that the window is more than 60 inches away from the bathroom door and well away from any stairway. What is the correct call?
  • The well is 52 inches deep measured from the ground surface to the bottom of the well, and its horizontal projection from the foundation wall is 36 inches. The applicable rules are a minimum 36-inch horizontal projection, a permanently affixed ladder or steps where the well depth exceeds 44 inches, and a limit of 6 inches on how far that ladder may encroach into the required dimensions. The contractor's ladder will project 5 inches into the well. What is the correct ruling?
  • Steel security bars have been installed over a bedroom emergency escape and rescue window. The bars are hinged so they swing completely clear of the opening, but they are held shut by a keyed padlock and the owner keeps the key in a kitchen drawer down the hall. How should the inspector rule on this installation?
  • The below-grade room has 150 square feet of floor area, holds only the furnace and the water heater, is reached by an interior stairway, and contains no sleeping room and no habitable space. The builder provided no emergency escape and rescue opening there. What is the correct ruling?
  • In one bedroom the operable sash has a bottom clear opening 20 inches above the finished floor, and the exterior grade below that window is 14 feet down. No opening control device or fall prevention device has been installed on the unit. How should the inspector rule?
  • The hallway running from the living area back to the bedrooms is framed so that the finished wall surfaces will stand 33 inches apart, and the builder argues that the width is adequate because every door opening off it is 32 inches wide. What is the correct inspector response?
  • At the top of the interior flight the framers provided no landing at all. The door at the head of the stairs is hung to swing away from the stairway into the kitchen, and the first step down begins immediately at the door threshold. How should the inspector rule?
  • The treads measure 10 1/4 inches deep, the risers are solid, and each tread nosing projects 1 1/2 inches beyond the riser face below it with a square edge. Riser heights and tread depths are uniform and otherwise within limits. How should the inspector rule on the nosing?
  • The spiral rises 111 inches from the garage floor to the loft floor and is cut with 12 risers. Clear width is 26 inches, headroom is 6 feet 8 inches, and tread depth measured 12 inches in from the narrow edge is 6 1/2 inches. For spiral stairways the minimum clear width is 26 inches, the maximum riser is 9 1/2 inches, the minimum headroom is 6 feet 6 inches and the minimum tread depth 12 inches from the narrow edge is 6 3/4 inches. What must the inspector cite?
  • The flight has 14 treads, and the total run measured horizontally from the face of the bottom riser to the face of the top riser is 133 inches. The nosings will project 1 inch. Tread depth is measured horizontally between the leading edges of adjacent treads, and the minimum tread depth is 10 inches. How should the inspector rule?
  • The handrail is a 1 1/2 inch round rail carried on brackets that hold it 1 inch clear of the finished wall surface. Its height above the nosing line is 36 inches and it runs continuously the full length of the flight. What should the inspector do?
  • The flight has three risers and two treads. All rises and runs are uniform and within the permitted limits, and no handrail has been installed on either side. The builder tells you a handrail was never called for on a flight this short. What is the correct ruling?
  • The walking surface of the raised platform is 26 inches above the patio slab directly below its edge. The ground then falls away into a garden terrace, so that at a point 30 inches horizontally out from the platform edge the surface below is 38 inches down. No guard was installed. A guard is required where a walking surface is more than 30 inches above the floor or grade below, measured within 36 inches horizontally from the edge. How should the inspector rule?
  • Working with a level and a rod you find the sloped surface climbs 24 inches over 24 feet of horizontal distance between the driveway and the entry door. Nothing has been mounted on either side of it, and its upper end runs straight into the door threshold with no level area in front of the door. The maximum slope permitted is 1 unit vertical in 12 units horizontal, and handrails become required where that figure is exceeded. What should the inspector cite?
  • The 2x10 ledger is bolted to the band joist with correctly sized fasteners at the required spacing and is properly flashed. Nothing else ties the deck framing back into the floor framing of the house. The builder states that the ledger bolts carry everything the deck can throw at the wall. What is the correct ruling?
  • Every deck joist stops against the face of the ledger and is held in place by three 10d toenails driven at an angle. No joist hangers or other approved connectors have been installed anywhere along the ledger. How should the inspector rule?
  • The ledger has been lag-screwed through the brick veneer and into what the contractor believes is the rim board behind it, using long lag screws with a bead of sealant at each hole. The veneer is a single wythe with an air space behind it. What should the inspector do?
  • One ceiling box sits 8 feet horizontally from the cooktop in the open kitchen, and the electrician intends to install an ionization smoke alarm there with no alarm-silencing feature. The permitted separations from a cooking appliance are 20 feet for an ionization alarm, 10 feet for an ionization alarm with an alarm-silencing feature, and 6 feet for a photoelectric alarm. How should the inspector rule?
  • The builder installed a single carbon monoxide alarm on the wall of the basement mechanical room next to the furnace, and none anywhere else in the house. All four bedrooms are on the second floor. How should the inspector rule?
  • The walls are covered with a decorative wood-look panel product applied over the gypsum board. The submittal the owner hands you lists a flame spread index of 210 and a smoke-developed index of 400 for the panel as tested. What should the inspector do?
  • A supply duct runs from the air handler in the garage through the common wall into the dwelling. The duct is flexible insulated ductwork with a plastic outer jacket, and the installer has also fitted a return grille in the garage ceiling to draw air from the garage back into the system. How should the inspector rule?
  • Every pane in a hazardous location is glass the builder states was ordered tempered, but no pane carries any manufacturer's designation in any corner, and the builder offers the glass supplier's invoice as proof of what was delivered. How should the inspector rule?
  • The fixed pane measures 36 inches wide by 60 inches tall. Its bottom edge is 14 inches above the finished floor, its top edge is 74 inches above the floor, and the floor in front of it is a walking surface. The glass is annealed. A horizontal wood rail 2 inches deep runs across the window 36 inches above the floor and is anchored to resist a horizontal load. The large-pane hazardous location criteria are a pane larger than 9 square feet, a bottom edge less than 18 inches above the floor, a top edge more than 36 inches above the floor and a walking surface within 36 inches. How should the inspector rule?
  • The exterior stair from the rear door down to the yard has no light fixture at any point along it. The interior stairways are lit and switched at both ends. The builder says the porch light around the corner at the front entry serves the whole exterior of the house. What should the inspector require?
  • The window well will project 40 inches horizontally out from the foundation wall. Applying the minimum net area of 9 square feet along with the minimum horizontal dimensions, what is the least width the well may have along the wall?
  • The flight has a total rise of 5 feet, and you measure the openings between treads at 5 1/2 inches. What is the correct finding on these open risers?
  • The space is now a closet with a door and a light, and the underside of the stair, the walls and the soffit inside it are all left as bare framing. What does the code require of this enclosure?
  • The rail is not circular, you measure its perimeter at 7 1/2 inches, and its sides are smooth with no groove or recess of any kind. What does the code require of a rail with this perimeter?
  • The 4x4 guard posts are notched around the outside of the rim joist, leaving about 1 1/4 inches of wood at the notch, and each is held by two lag screws into the rim. How should the inspector judge this connection?
  • The bottom riser lands directly on the lawn, with no landing surface of any kind, and the builder points out that the grade there is flat and the sod is well established. What does the code require at the bottom of this flight?
  • The hallway alarm outside the bedrooms sits on the ceiling 20 inches horizontally from the open doorway of a hall bathroom that contains a tub and shower. How should the inspector judge that location?
  • The bottom exposed edge of the fixed glazing sits 12 inches above the floor a bather stands on, the glass is 4 feet from the water's edge, and the panes are ordinary annealed glass. What is the correct finding?
  • The great room is 600 square feet, the loft is 240 square feet, and the clear height measures 7 feet 4 inches both above the loft floor and beneath it. How should the inspector judge the loft?
  • The pane measures 30 inches wide by 42 inches high, its bottom edge is 16 inches above the finished floor, its top edge is 58 inches above the floor, and the floor is a walking surface right up to the wall. Is this a hazardous location under the large-pane rule?
  • The plan permits the beam to cantilever past the end post by not more than one-quarter of the beam span, the posts are 8 feet apart, and the builder ran the beam 3 feet past the last post. What is the permitted overhang, and does this beam comply?
  • The upper level has a smoke alarm outside the bedrooms and one in each bedroom, and the electrician installed none on the family room level. How should the inspector judge that arrangement?
  • You measure the slope at 1 unit vertical in 10 units horizontal, and no handrail has been installed on either side of the sloped portion. What does the code require here?
  • The approved plan reproduces the post height table for this material: 4x4 posts to a maximum height of 8 feet, 4x6 to 8 feet, and 6x6 to 14 feet. You measure the tallest 4x4 post at 10 feet from the top of its footing to the underside of the beam. What is the finding?
  • Each door is a swinging door with eight divided lites of clear annealed glass, and each lite measures 6 inches by 8 inches within true wood muntins. What is the correct finding on this glazing?
  • The bedroom's escape and rescue window meets every dimension, but it opens into the new screened porch, which is fully enclosed and reached only through a door on the far side. How should the inspector judge that opening?
  • The clear distance between two posts is 60 inches, the balusters are 1 1/2 inches wide, and the openings must not allow a 4 3/8-inch sphere to pass. What is the fewest balusters that will work in this bay?
  • The device serves the converted attic, which contains a bedroom and a full bathroom and is the only way in or out of that floor. How should the inspector judge this installation?
  • A fixed pane in the family room wall measures 48 inches wide by 32 inches high, its bottom edge is 4 inches above the finished floor, and the floor in front of it is a walking surface right up to the wall. The glass is annealed. The large-pane criteria are an individual pane larger than 9 square feet, a bottom edge less than 18 inches above the floor, a top edge more than 36 inches above the floor, and a walking surface within 36 inches. What is the finding?
  • The window glass measures 24 inches by 60 inches, its bottom exposed edge is 48 inches above the floor a bather stands on, and measured horizontally in a straight line the glass is 72 inches from the water's edge of the tub. The glass is annealed. What is the finding?
  • Each in-fill panel measures 24 inches by 30 inches and its bottom edge sits 38 inches above the deck walking surface. The glass is annealed and carries no marking. The builder points out that each panel is well under 9 square feet and that its bottom edge is far above 18 inches. What is the finding?
  • A fixed pane in that wall measures 30 inches wide by 48 inches tall, and the bottom exposed edge of the glass is 28 inches above the walking surface of the ramp running past it. The glass is annealed. The builder points out that the bottom edge is well above 18 inches, so the four large-pane criteria are not all satisfied. What is the finding?
  • Each of the two panels measures 34 inches wide by 76 inches tall. The moving panel is tempered and marked, and the fixed panel is annealed with no marking of any kind. The builder explains that only the panel that moves can be walked into, since the other one is held in the frame. What is the finding?
  • The unit holds two fixed panes separated by a structural mullion, and each pane measures 30 inches wide by 40 inches high. The bottom edge of the glass is 12 inches above the finished floor, the top edge is 52 inches above the floor, and a walking surface runs right up to the wall. The glass is annealed. What is the finding under the large-pane rule?
  • The pane measures 42 inches wide by 80 inches tall, a walking surface runs up to it, and its top edge is far above 36 inches. The four large-pane criteria are an individual pane larger than 9 square feet, a bottom edge less than 18 inches above the floor, a top edge more than 36 inches above the floor, and a walking surface within 36 inches. Leaving the other criteria as they are, how high would the bottom exposed edge have to sit for this rule to stop applying?
  • The total rise from the lower finished floor to the upper finished floor measures 105 inches, and the maximum riser height is 7 3/4 inches. What is the fewest risers this flight may have, and what riser height results?
  • The stair will have 15 risers, and the minimum tread depth that applies is 10 inches. Working only from the treads, what is the least horizontal run the flight itself requires?
  • The total rise from the basement finished floor to the first floor finished floor measures 168 inches, and the framer has cut the stringers for 22 risers with no landing anywhere in the run. A flight is limited to a vertical rise of 151 inches between floor levels or landings. What is the finding?
  • Measured from the sloped line touching the tread nosings, the headroom along the flight is 6 feet 10 inches. Over the landing, measured vertically from the landing floor surface to the underside of the soffit, the clear height is 6 feet 5 inches. What is the finding?
  • With the sash swung clear, the opening measures 22 inches wide by 41 inches high, and the sill of the openable portion is 40 inches above the finished floor. The opening is above grade, so the area required is 5.7 square feet, with a clear width of not less than 20 inches, a clear height of not less than 24 inches, and a sill height of not more than 44 inches. What is the finding?

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