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NASCLA ACCREDITED EXAM / NASCLA ACCREDITED EXAM PREP/
NASCLA ACCREDITED EXAM PRACTICE ACTUAL EXAM 250 QUESTIONS
AND CORRECT DETAILED ANSWERS WITH RATIONALES2025/2026
(VERIFIED ANSWERS) | A+GRADE
How shall a regulator to a cylinder valve be connected? - ......ANSWER........The valve shall
be opened slightly and closed immediately. (The action is generally termed "cracking" and
is intended to clear the valve of dust or dirt that might otherwise enter the regulator.) The
person cracking the valve shall stand to one side of the outlet, not in front of it. The valve of
fuel gas cylinder shall not be cracked where the gas would reach welding work, sparks,
flame, or other possible sources of ignition.
All hose in use, carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or
substance which may ignite or enter combustion, or be in any way harmful to employees
shall? - ......ANSWER........Be inspected at the beginning of each working shift. Defective
hose shall be removed from service.
When the arc welder or cutter has occasion to leave his work or to stop work for any
appreciable length of time, or when the arc welding or cutting machine is to be moved,
what should happen? - ......ANSWER........The power supply switch to the equipment shall
be opened.
Lifelines. Where a welder must enter a confined space through a manhole or other small
opening, what should occur? - ......ANSWER........Means shall be provided for quickly
removing him in case of emergency. When safety belts and lifelines are used for this
purpose, they shall be so attached to the welder's body that his body cannot be jammed in
a small exit opening. An attendant with a pre-planned rescue procedure shall be stationed
outside to observe the welder at all times and be capable of putting rescue operations into
effect.
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Working Clearances (voltage) - ......ANSWER........1. Nominal voltage to ground, 0-150 =
Minimum clear distance for conditions is 3 ft, 3ft, 3ft 2. Nominal voltage to ground, 151-600
= Minimum clear distance for conditions is 3ft, 3.5ft, 4ft
Minimum Depth of Clear Working Space in Front of Electrical Equipment
- ......ANSWER........1. Nominal voltage to ground, 601 to 2,500 = Conditions 3ft, 4ft, 5ft 2.
Nominal voltage to ground, 2,501 to 9,000 = Conditions 4ft, 5ft, 6ft 3. Nominal voltage to
ground, 9,001 to 25,000 = Conditions 5ft, 6ft, 9ft 4. Nominal voltage to ground, 25,001 to
75kV = Conditions 6ft, 8ft, 10ft 5. Nominal voltage to ground, Above 75kV = Conditions 8ft,
10ft, 12ft
Each scaffold and scaffold component shall be capable of support, without failure, what?
- ......ANSWER........Its own weight and at least 4 times the maximum intended load applied
or transmitted too it
Each scaffold unit shall be installed so that the space between adjacent units and the
space between the platform and the uprights is? - ......ANSWER........No more than 1 inc
(2.5cm) wide, except where the employer can demonstrate that a wider space is necessary
(for example, to fit around uprights when side brackets are used to extend the width of the
platform)
Each scaffold platform and walkway shall be? - ......ANSWER........At least 18 inches
(46cm) side
The front edge of the platforms shall - ......ANSWER........Not be more than 14 inches
(36cm) from the face of the work, unless guardrail systems are erected along the front
edge and/or personal fall arrest systems are used in accordance with paragraph G
The maximum distance from the face for outrigger scaffolds shall be? - ......ANSWER........3
inches (8cm)
The maximum distance from the face for plastering and lathing operations shall be?
- ......ANSWER........18 inches (46cm)
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Each end of a platform, unless cleated or otherwise restrained by hooks or equivalent
means, shall? - ......ANSWER........Extend over the centerline of its support at least 6 inches
(15 cm)
Each end of a platform 10 feet or less in length shall? - ......ANSWER........Not extend over
its support more than 12 inches (30 cm) unless the platform is designed and installed so
that the cantilevered portion of the platform is able to support employees and/or materials
without tipping, or has guardrails which block employee access to the cantilevered end
On scaffolds where platforms are overlapped to create a long platform, the overlap shall?
- ......ANSWER........Occur only over supports, and shall not be less than 12 inches (30 cm)
unless the platforms are nailed together or otherwise restrained to prevent movement
Scaffold components manufactured by different manufacturers shall not be?
- ......ANSWER........Intermixed unless components fit together without force and structural
integrity is maintained by the user. Components shall not be modified to intermix them
unless a competent person determines the resulting scaffold is structurally sound.
Supported scaffold poles, legs, posts, frames, and uprights shall? - ......ANSWER........Bear
on base plates and mud sills or other adequate firm foundation. Footings shall be level.
Unstable objects shall not be used. Front-end loaders and similar equipment shall not be
used for support unless they are specifically designed by the manufacturer. Fork-lifts shall
not be sued.
Fall protection: Each employee on a scaffold more than 10 feet (3.1m) above a lower level
shall be protected from falling to that lower level. - ......ANSWER........Each employee on a
boatswains' chair, catenary scaffold, float scaffold, needle beam scaffold, or ladder jack
scaffold shall be protected by a personal fall arrest system. Each employee on a single-
point or two-point adjustable suspension scaffold shall be projected by both personal fall
arrest system and guardrail system. Each employ on a crawling board (chicken ladder)
shall be protected, a guardrail system (200lb minimum) or by 3/4" diameter grabline or
equivalent handhold securely fastened beside each crawling board. Each employee on a
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self-contained adjustable scaffold shall be protected by a guardrail system (200lb min).
Each employ on a walkway located within a scaffold shall be protected by a guardrail
system (200lb min) installed within 9.5 in of and along at least one side of the walkway.
Each employee performing overhand bricklaying operations from a supported scaffold
shall be protected from falling from all open sides and ends of the scaffold (except at the
side next to the wall being laid) using a personal fall arrest system or guardrail system (200
lbs. min).
The top edge height of top rails or equivalent member on support scaffolds manufactured
or placed in service after January 1, 2000, shall be? - ......ANSWER........Installed between
38 inches (.97m) and 45 inches (1.2m) above the platform surface. The top edge height on
supported scaffolds manufactured and placed in service before Jan 1, 2000, and on all
suspended scaffolds where both guardrail and a personal fall arrest system are required
shall be between 36 inches and 45 inches. When conditions warrant, the height of the top
edge may exceed the 45-inch height, provided the guardrail system meets all other criteria.
Scaffold casters and wheels shall be? - ......ANSWER........Locked with positive wheel
and/or wheel and swivel locks, or equivalent means, to prevent movement of the scaffold
while the scaffold is used on stationary manner.
Each employee who is constructing a leading edge 6 feet or more above lower levels shall
be protected from falling by a guardrail systems, safety net systems, or personal fall arrest
systems. - ......ANSWER........Exception: When the employer can demonstrate that it is
infeasible or creates a grater hazard to use these systems, the employer shall develop and
implement a fall protection plan which meets the requirements.
Each employee reaching more than 10 inches below the level of walking/working surface
on which they are working, shall - ......ANSWER........Be protected from falling by a guardrail
system, safety net system, or personal fall arrest system.
Wall openings - ......ANSWER........Each employee working on , at, above, or near wall
openings (including those with chutes attached) where the outside bottom edge of the wall
NASCLA ACCREDITED EXAM / NASCLA ACCREDITED EXAM PREP/
NASCLA ACCREDITED EXAM PRACTICE ACTUAL EXAM 250 QUESTIONS
AND CORRECT DETAILED ANSWERS WITH RATIONALES2025/2026
(VERIFIED ANSWERS) | A+GRADE
How shall a regulator to a cylinder valve be connected? - ......ANSWER........The valve shall
be opened slightly and closed immediately. (The action is generally termed "cracking" and
is intended to clear the valve of dust or dirt that might otherwise enter the regulator.) The
person cracking the valve shall stand to one side of the outlet, not in front of it. The valve of
fuel gas cylinder shall not be cracked where the gas would reach welding work, sparks,
flame, or other possible sources of ignition.
All hose in use, carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or
substance which may ignite or enter combustion, or be in any way harmful to employees
shall? - ......ANSWER........Be inspected at the beginning of each working shift. Defective
hose shall be removed from service.
When the arc welder or cutter has occasion to leave his work or to stop work for any
appreciable length of time, or when the arc welding or cutting machine is to be moved,
what should happen? - ......ANSWER........The power supply switch to the equipment shall
be opened.
Lifelines. Where a welder must enter a confined space through a manhole or other small
opening, what should occur? - ......ANSWER........Means shall be provided for quickly
removing him in case of emergency. When safety belts and lifelines are used for this
purpose, they shall be so attached to the welder's body that his body cannot be jammed in
a small exit opening. An attendant with a pre-planned rescue procedure shall be stationed
outside to observe the welder at all times and be capable of putting rescue operations into
effect.
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Working Clearances (voltage) - ......ANSWER........1. Nominal voltage to ground, 0-150 =
Minimum clear distance for conditions is 3 ft, 3ft, 3ft 2. Nominal voltage to ground, 151-600
= Minimum clear distance for conditions is 3ft, 3.5ft, 4ft
Minimum Depth of Clear Working Space in Front of Electrical Equipment
- ......ANSWER........1. Nominal voltage to ground, 601 to 2,500 = Conditions 3ft, 4ft, 5ft 2.
Nominal voltage to ground, 2,501 to 9,000 = Conditions 4ft, 5ft, 6ft 3. Nominal voltage to
ground, 9,001 to 25,000 = Conditions 5ft, 6ft, 9ft 4. Nominal voltage to ground, 25,001 to
75kV = Conditions 6ft, 8ft, 10ft 5. Nominal voltage to ground, Above 75kV = Conditions 8ft,
10ft, 12ft
Each scaffold and scaffold component shall be capable of support, without failure, what?
- ......ANSWER........Its own weight and at least 4 times the maximum intended load applied
or transmitted too it
Each scaffold unit shall be installed so that the space between adjacent units and the
space between the platform and the uprights is? - ......ANSWER........No more than 1 inc
(2.5cm) wide, except where the employer can demonstrate that a wider space is necessary
(for example, to fit around uprights when side brackets are used to extend the width of the
platform)
Each scaffold platform and walkway shall be? - ......ANSWER........At least 18 inches
(46cm) side
The front edge of the platforms shall - ......ANSWER........Not be more than 14 inches
(36cm) from the face of the work, unless guardrail systems are erected along the front
edge and/or personal fall arrest systems are used in accordance with paragraph G
The maximum distance from the face for outrigger scaffolds shall be? - ......ANSWER........3
inches (8cm)
The maximum distance from the face for plastering and lathing operations shall be?
- ......ANSWER........18 inches (46cm)
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Each end of a platform, unless cleated or otherwise restrained by hooks or equivalent
means, shall? - ......ANSWER........Extend over the centerline of its support at least 6 inches
(15 cm)
Each end of a platform 10 feet or less in length shall? - ......ANSWER........Not extend over
its support more than 12 inches (30 cm) unless the platform is designed and installed so
that the cantilevered portion of the platform is able to support employees and/or materials
without tipping, or has guardrails which block employee access to the cantilevered end
On scaffolds where platforms are overlapped to create a long platform, the overlap shall?
- ......ANSWER........Occur only over supports, and shall not be less than 12 inches (30 cm)
unless the platforms are nailed together or otherwise restrained to prevent movement
Scaffold components manufactured by different manufacturers shall not be?
- ......ANSWER........Intermixed unless components fit together without force and structural
integrity is maintained by the user. Components shall not be modified to intermix them
unless a competent person determines the resulting scaffold is structurally sound.
Supported scaffold poles, legs, posts, frames, and uprights shall? - ......ANSWER........Bear
on base plates and mud sills or other adequate firm foundation. Footings shall be level.
Unstable objects shall not be used. Front-end loaders and similar equipment shall not be
used for support unless they are specifically designed by the manufacturer. Fork-lifts shall
not be sued.
Fall protection: Each employee on a scaffold more than 10 feet (3.1m) above a lower level
shall be protected from falling to that lower level. - ......ANSWER........Each employee on a
boatswains' chair, catenary scaffold, float scaffold, needle beam scaffold, or ladder jack
scaffold shall be protected by a personal fall arrest system. Each employee on a single-
point or two-point adjustable suspension scaffold shall be projected by both personal fall
arrest system and guardrail system. Each employ on a crawling board (chicken ladder)
shall be protected, a guardrail system (200lb minimum) or by 3/4" diameter grabline or
equivalent handhold securely fastened beside each crawling board. Each employee on a
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self-contained adjustable scaffold shall be protected by a guardrail system (200lb min).
Each employ on a walkway located within a scaffold shall be protected by a guardrail
system (200lb min) installed within 9.5 in of and along at least one side of the walkway.
Each employee performing overhand bricklaying operations from a supported scaffold
shall be protected from falling from all open sides and ends of the scaffold (except at the
side next to the wall being laid) using a personal fall arrest system or guardrail system (200
lbs. min).
The top edge height of top rails or equivalent member on support scaffolds manufactured
or placed in service after January 1, 2000, shall be? - ......ANSWER........Installed between
38 inches (.97m) and 45 inches (1.2m) above the platform surface. The top edge height on
supported scaffolds manufactured and placed in service before Jan 1, 2000, and on all
suspended scaffolds where both guardrail and a personal fall arrest system are required
shall be between 36 inches and 45 inches. When conditions warrant, the height of the top
edge may exceed the 45-inch height, provided the guardrail system meets all other criteria.
Scaffold casters and wheels shall be? - ......ANSWER........Locked with positive wheel
and/or wheel and swivel locks, or equivalent means, to prevent movement of the scaffold
while the scaffold is used on stationary manner.
Each employee who is constructing a leading edge 6 feet or more above lower levels shall
be protected from falling by a guardrail systems, safety net systems, or personal fall arrest
systems. - ......ANSWER........Exception: When the employer can demonstrate that it is
infeasible or creates a grater hazard to use these systems, the employer shall develop and
implement a fall protection plan which meets the requirements.
Each employee reaching more than 10 inches below the level of walking/working surface
on which they are working, shall - ......ANSWER........Be protected from falling by a guardrail
system, safety net system, or personal fall arrest system.
Wall openings - ......ANSWER........Each employee working on , at, above, or near wall
openings (including those with chutes attached) where the outside bottom edge of the wall
