www.cdc.gov/niosh/face

DATE: 

April 18, 2013

TIME:

9:45 a.m. 

VICTIMS:

24-year old Hispanic

Labor and a 37-year old

Hispanic Pipefitter

INDUSTRY/NAICS CODE:

Construction/23

EMPLOYER: 

Commercial building

contractor & 

subcontractors

SAFETY & TRAINING:

The contractor did, but

some subcontractors 

did not

SCENE: 

Retail development area

LOCATION:

Tennessee

EVENT TYPE:

Struck by

___________________________

INCIDENT HIGHLIGHTS

REPORT#: 2014-02 REPORT DATE: January 30, 2018

Revised Date: June 19, 2020

Laborer, Pipefitter, and Utility Foreman 

Crushed by Falling Block Wall—Tennessee

________________________________________________________ 

SUMMARY

On April 18, 2013, a 24-year-old Hispanic laborer and a 37-year-old 

Hispanic pipefitter were crushed by a falling block wall when it 

failed; they died immediately of their injuries. A 46-year-old utility 

foreman was also injured in the incident. At the time of the incident, 

the laborer was applying caulking to the expansion joints of a block 

wall, and the pipefitter and the utility foreman were installing piping 

for the building’s sprinkler system... READ THE FULL REPORT> (p.3)

________________________________________________________ 

CONTRIBUTING FACTORS

Key contributing factors identified in this investigation include:

• Deviation from engineering drawings

• Inadequate inspection of rebar placement

• Inadequate bracing for the block wall

• Wall height extending too far above the bracing LEARN MORE>

(p.9)

______________________________________________________ 

RECOMMENDATIONS

NIOSH investigators concluded that, to help prevent similar 

occurrences, employers should: 

• Ensure that employees follow the engineering/architectural

drawings during building construction and obtain engineering

approval before plan changes are made.

• Develop and follow a masonry wall bracing plan, train employees

on proper masonry wall bracing, and ensure masonry walls are

properly braced throughout the project.

• Develop and implement a restricted/limited access

zone. LEARN MORE> (p.9)
Page 2

NIOSH • 304-285-5916

1095 Willowdale Road

Morgantown, West Virginia 

26505

Fatality Assessment and Control Evaluation (FACE) Program

The National Institute for Occupational Safety and Health (NIOSH), an institute within the Centers for Disease Control and Prevention 

(CDC), is the federal agency responsible for conducting research and making recommendations for the prevention of work-related 

injury and illness. In 1982, NIOSH initiated the Fatality Assessment and Control Evaluation (FACE) Program. FACE examines the

circumstances of targeted causes of traumatic occupational so that safety professionals, researchers, employers, trainers, and workers 

can learn from these incidents. The primary goal of these investigations is for NIOSH to make recommendations to prevent similar

occurrences. These NIOSH investigations are intended to reduce or prevent occupational deaths and are completely separate from the 

rule making, enforcement and inspection activities of any other federal or state agency. Under the FACE program, NIOSH investigators 

interview persons with knowledge of the incident and review available records to develop a description of the conditions and 

circumstances leading to the deaths in order to provide a context for the agency’s recommendations. The NIOSH summary of these 

conditions and circumstances in its reports is not intended as a legal statement of facts. This summary, as well as the conclusions and 

recommendations made by NIOSH, should not be used for the purpose of litigation or the adjudication of any claim. For further 

information, visit the program website at www.cdc.gov/niosh/face/ or call toll free at 1-800-CDC-INFO (1-800-232-4636).
REPORT#: 2014-02 Page 3

SUMMARY

On April 18, 2013, a 24-year-old Hispanic laborer and a 37-year-old Hispanic pipefitter were crushed by a falling block 

wall when it failed; they died immediately of their injuries. A 46-year-old utility foreman was also injured in the incident. 

At the time of the incident, the laborer was applying caulking to the expansion joints of a block wall, and the pipefitter 

and the utility foreman were installing piping for the building’s sprinkler system in a trench next to the block wall. A wind

gust caused the block wall to fall onto the laborer, pipefitter, and utility foreman. The project superintendent called 911, 

and emergency medical services were dispatched and arrived at the incident within 4 minutes. The laborer and 

pipefitter were pronounced dead at the scene, and the utility foreman was airlifted to a local hospital.

INTRODUCTION

At 9:45 a.m. on April 18, 2013, an Hispanic laborer and Hispanic pipefitter were killed and a utility foreman was injured 

when an inadequately braced 24 foot tall block wall they were working near fell on them during a 33-mph wind gust. On 

November 19, 2013, the Tennessee Department of Labor and Workforce Development/Occupational Safety and Health 

Division (TOSHA) notified the National Institute for Occupational Safety and Health (NIOSH), Division of Safety Research, 

of the incident. On September 9, 2014, a NIOSH health scientist conducted an investigation of the fatality and reviewed 

circumstances of the incident with the investigating TOSHA safety compliance officer. Photographs of the incident site 

and witness statements taken by TOSHA and the fire department were reviewed. 

EMPLOYERS

• The prime contractor, a commercial building contractor, had 75 employees, had been in business for 21 years, and 

had 3 employees on-site the day of the incident. The prime contractor had hired three subcontractors to complete 

the commercial building project. 

• The masonry subcontractor had 14 employees, had been in business for 2 years, and had 5 employees on-site the day 

of the incident. 

• The excavation subcontractor had 14 employees, had been in business since 1963, and had 3 employees on-site the 

day of the incident. 

• The waterproofing subcontractor had 46 employees, had been in business for 8 years, and had 3 employees on-site 

the day of the incident.

WRITTEN SAFETY PROGRAMS and TRAINING

At the time of the incident, according to TOSHA, the masonry subcontractor had an employee safety manual that 

included a special emphasis checklist, a section on structure construction, a section on wall bracing to prevent collapse, 

and training on restricted/limited access areas. The employees for the masonry subcontractor had been trained on 

April 4, 2013. The excavation subcontractor did not have a comprehensive safety and health plan but provided verbal 

on-the-job training in English. The excavation subcontractor provided hard hats and high visibility safety vests. The 

waterproofing subcontractor did not have a comprehensive safety and health plan and there was no evidence of 

worker training.

WORKER INFORMATION

The 24-year-old male Hispanic laborer who worked for the waterproofing subcontractor, was from Mexico, and his first 

language was Spanish, but he could speak some English. At time of the incident, the laborer was not wearing personal 

protective equipment. The 37-year-old Hispanic pipefitter who worked for the excavation subcontractor, was from 
REPORT#: 2014-02 Page 4

Mexico, had been in the United States for 17 years, and his first language was Spanish, but he spoke English. At the time 

of the incident the pipefitter was wearing a high-visibility vest. The 46-year-old utility foreman who worked for the 

excavation subcontractor, was injured when the block wall collapsed, and was wearing a high-visibility vest. 

INCIDENT SCENE

The building being constructed was a 28,000-square-foot retail store in a retail development area. Construction began 

in March of 2013 with a concrete footer measuring 2 feet wide and 1 foot deep. Rebar was to be placed 40 inches on 

center in the footer. The walls were constructed of typical concrete masonry unit blocks that were 8 inches tall, 8 inches 

wide, and 16 inches long. The walls were 36 courses (24 feet) tall and consisted of panels, with masonry control joints 

between each panel. Masonry control joints prevent the wall from cracking caused by shrinkage, wind, soil pressure, 

seismic forces, or settlement. The masonry walls were completed at different times so they were all in different stages in 

their curing process. The west wall was completed on March 26, the east wall was completed on 

April 3, the north wall was completed on April 5, and the south wall was completed on April 12. On the day of the 

incident the masonry subcontractor’s 5 employees were in the process of constructing the loading dock wall (Diagram). 

Prior to building the east wall, the masonry subcontractor noticed the rebar in the east wall footer was not positioned in 

the center of the footer according to the engineering drawings, but was 2 to 4 inches off center, positioning them near 

the exterior of the wall. The masonry subcontractor notified the prime contractor of the error, and the prime contractor 

instructed the masonry contractor to fix it by bending the rebar toward the center of the footer so it would fit inside the 

center of the blocks. The out-of-place rebar went unnoticed by the engineer during inspection and the engineer was not 

notified of the change in the rebar. 

The east wall, the incident wall, was 149 feet long and was not structurally tied to the other three walls at the time of 

the incident. The east wall had seven panels, with a control joint between each panel. The east wall was originally 

braced with three wooden braces on the inside and three wooden braces on the outside, with the braces opposing each 

other. The braces consisted of three pieces: one vertical scaffold board, positioned on the wall but not attached to the 

wall; a cleat board measuring 2-inch by 4-inch placed horizontally across the vertical scaffold board approximately 9 to 

101⁄2 feet up the scaffold board (Photo 1); and another scaffold board was wedged at an angle between the cleat and a 

4-foot long piece of rebar driven into the ground. Two masonry blocks were placed on top of the rebar and board as 

extra weight for the scaffold board and as protection around the rebar (Photo 2). The spacing between braces varied, as 

did the angle of the braces (Photo 3). Two of the three outside braces were removed, leaving one brace in the center of 

the outside wall the day before the incident to allow the waterproofing subcontractor to caulk the control joints. No 

permanent supporting elements of the structure were in place. A 3 foot deep, 51⁄2 foot wide, and 8 foot long trench ran 

parallel to the east wall. The trench was positioned 15 feet from the wall and was dug to allow installation of the 

building’s sprinklers back-flow system. There was a 31⁄2-foot tall concrete meter box toward the south end of the trench 

that was being used as a table (Photo 4).
REPORT#: 2014-02 Page 5

Diagram. Incident scene.
REPORT#: 2014-02 Page 6

 Photo 1. Top cleat of wall brace. Photo 2. Blocks and rebar used to secure wall 

 (Photo courtesy of TOSHA.) brace. (Photo courtesy of TOSHA.)

Photo 3. Interior wall bracing. (Photo courtesy of TOSHA.)
REPORT#: 2014-02 Page 7

WEATHER

The weather on the day of the incident was approximately 80 degrees Fahrenheit, 65% humidity, 18 mph average 

southerly wind speed, 32 mph maximum wind speed, and 39 mph wind gusts [Weather Underground 2013]. The 

weather is believed to have been a factor in this incident.

INVESTIGATION

The excavation crew arrived at work on April 18, 2013, around 6 a.m. The masonry crew arrived around 7:30 a.m. 

The waterproofing crew arrived at work at 8 a.m. Between 9 and 9:15 a.m., the subcontractor crews took a break and 

returned to work around 9:30 a.m. The waterproofing laborer (decedent) was caulking the control joints on the east 

wall from a 16-foot fiberglass extension ladder. Two other waterproofing crew members were spraying waterproofing 

on the south wall. The three excavation crew members, including the utility foreman (injured) and pipefitter (decedent), 

were in the trench installing a backflow preventer for the building’s sprinkler system. The foreman for the masonry 

subcontractor was meeting with the prime contractor and a framing subcontractor at the south end of the project. 

The four other employees for the masonry subcontractor were constructing the loading dock wall on the north side 

(Diagram).

Photo 4. Concrete meter box. Arrow indicates where three excavation employees were working.

(Photo courtesy of TOSHA.)
REPORT#: 2014-02 Page 8

At 9:45 a.m., the east wall fell during a 33-mph wind gust, on top of the waterproofing laborer, the pipefitter, and 

the utility foreman (Photo 5). The excavation foreman was able to run to safety. Once the wall fell, the project 

superintendent called 911 and emergency medical services (EMS) were dispatched and arrived within four minutes. 

Several crew members ran to remove the block wall from the utility foreman before EMS arrived. The laborer and 

pipefitter were pronounced dead at the scene. The utility foreman was airlifted to a local hospital.

CAUSE OF DEATH 

According to the TOSHA report, the cause of death was multiple blunt force injuries.

Photo 5. Collapsed wall.

(Photo courtesy of TOSHA.)
REPORT#: 2014-02 Page 9

CONTRIBUTING FACTORS 

Occupational injuries and fatalities are often the result of one or more contributing factors or key events in a larger 

sequence of events that ultimately result in the injury or fatality. NIOSH investigators identified the following 

unrecognized hazards as key contributing factors in this incident:

• Deviation from engineering drawings 

• Inadequate inspection of rebar placement

• Inadequate bracing for the block wall

• Wall height extending too far above the bracing 

• Worker proximity to unbraced block wall

• Lack of competent person to monitor wind speed

• Inadequate training related to masonry wall safety

RECOMMENDATIONS/DISCUSSION

Recommendation #1: Employers should ensure that employees follow the engineering/architectural drawings during 

building construction and obtain engineering approval before plan changes are made.

Discussion: Based on the original engineering drawing, with rebar placed in the center of each block and secured with 

grout, the unsupported block wall in the intermediate period should have been able to sustain wind speeds up to 35 

mph [MIOSHA 2010; MCCA 2012; NMCA 2005; NCMA 2014]. Additionally, masonry control joints were designed to 

prevent wall damage due to cracking caused by shrinkage, wind, soil pressure, seismic forces, or settlement. The wall 

panels were designed to fail independently in the event of a wind gust. The rebar dowel coming out of the footer for the 

east wall was not placed in the center of the footer as specified in the engineering drawings, but was off-center by 2 to 4 

inches toward to exterior edge [Photo 6]. The engineer did not notice the misplacement of the rebar during inspections. 

The masonry subcontractor brought the rebar placement issue to the attention of the general contractor. The masonry 

subcontractor was instructed to fix the problem by bending the rebar toward the center of the footer to fit within the 

centers of the concrete masonry blocks. The resultant rebar/grout combination was no longer strong enough to resist 

the lateral loads of the wind coming from the west, based on an analysis conducted by the OSHA Directorate of 

Construction, Engineering Services section, at the request of TOSHA, and the wall presented properties similar to an 

unreinforced wall design. This rebar misalignment was consistent across all seven wall panels that failed. Procedures to 

address this issue include placing the rebar dowels in the center of the blocks according to the engineering drawing or 

correcting the misalignment by drilling correctly positioned holes in the grout and epoxying rebar in place.
REPORT#: 2014-02 Page 10

Recommendation #2: Employers should develop and follow a masonry wall bracing plan, train employees on proper 

masonry wall bracing, and ensure masonry walls are properly braced throughout the project.

Discussion: Employers should develop a masonry wall bracing plan before construction begins. A masonry wall bracing 

plan includes notification criteria and detailed bracing locations, based on masonry wall structure and construction 

periods. The notification criteria details who is responsible for the erection and dismantling of the bracing, monitoring 

wind speeds, and establishing restricted/limited access zones. The plan also delineates who has the authority to 

supervise subcontractors and employees who work in the restricted/limited access zone and how to communicate 

the plan. 

OSHA regulation 29CFR1926.706(b) states that all masonry walls over 8 feet in height shall be “adequately braced” to 

prevent overturning and to prevent collapse unless the wall is adequately supported such that it will not overturn or 

collapse. The bracing shall remain in place until permanent supporting elements of the structure are in place. Permanent 

supporting elements include roof systems, trusses, and decking [OSHA 1988]. There is no additional guidance from OSHA 

on what is meant by “adequately braced”, how to adequately brace a wall, or what comprises an adequately brace, but 

OSHA recommends bracing should follow guidelines provided by industry associations and organizations like the Mason 

Contractors Association of America (MCCA) and National Concrete Masonry Association (NCMA). 

Photo 6. Rebar coming out of footer.

(Photo courtesy of TOSHA.)
REPORT#: 2014-02 Page 11

OSHA does not require that employers train employees on proper masonry wall bracing. However, the MCAA 

recommends employers provide training to those employees engaged in masonry activities. Michigan OSHA (MIOSHA) 

requires the use of bracing plans or the use of a registered professional engineer like those found in the Standard 

Practice for Bracing Walls Under Construction or Masonry Wall Bracing Design Handbook [MIOSHA 2015a]. Other states 

have provided requirements beyond the federal OSHA standard and added masonry wall bracing requirements of their 

own [Oregon OSHA 2003]. Bracing guidelines have also been developed by the MCAA [MCAA 2012]. Additionally, the 

NCMA recommends alternative bracing systems should be approved by a registered professional engineer [NCMA 2014]. 

The bracing locations should be identified before work begins to maximize safety and efficiency. This allows the 

contractor to delineate the restricted/limited access zone throughout the life of the project [Johnson 2008].

Factors that affect wall bracing design include period of construction, density of wall material, wall length, control joints, 

wall height, wall thickness, method of grouting, age of grout, and wind speed. Bracing materials include pipe bracing, 

cable bracing, and wood bracing. Wood bracing is common, although pipe bracing provides more resistance to wind 

loads than wood or cable. Cable braces require bracing on both sides to apply constant tension on the wall [Palmer 

2000]. Standard industry practice recommendations allow a length of a wall between control joints of approximately 25 

feet for concrete and clay masonry units, with a minimum of two braces per panel on each side of the wall (four total), 

and the braces need to be within 20% of the distance from each end of the panel (Figure 1). The east wall had seven 

panels and should have had fourteen braces on each side based on the MCAA guidelines. The entire 149-foot east wall 

was braced with one exterior brace and three interior braces.

The wall bracing system used in this incident was a modified triangle system and composed of two scaffold boards. The 

vertical board was positioned on the wall but not attached to the wall. The vertical board had a 2- by 4-foot cleat across 

it horizontally (Photo 1 and Photo 3). The inclined brace boards were wedged at an angle that varied between 34 and 41 

degrees. A 4-foot length of rebar was driven into the ground; one masonry block was placed over the rebar with the 

other placed on top of the inclined board (Photo 2 and Photo 3). There was no permanent tie from the ground to the 

wall brace. The wall extended between 131⁄2 and 15 feet above the brace. 

The MCCA Standard Practice for Bracing Masonry Walls Under Construction recommends that for a 23-foot, 4-inch wall 

with 8-inch block, reinforced with No. 5 rebar 4 feet on center, the wall should extend no more than 8 feet, 8 inches 

above the brace and the angle of the inclined brace should be between 35 and 45 degrees. A typical triangle wood 

bracing system should include a horizontal brace, a vertical brace, a diagonal brace positioned with a cleat on both ends 

of the brace, and a diagonal stiffener anchored to the wall or footer and nailed to the diagonal brace [MCCA 2012] 

(Figures 2 and 3). Michigan OSHA requires the masonry contractor to maintain a copy of the Masonry Wall Bracing 

Design Handbook or other permitted method of bracing on the jobsite [MIOSHA 2015a]. 

In this incident, the wall extended more than 8 feet 8 inches above the braces in some instances, and several of the 

recommended brace system components were missing. If a masonry wall bracing plan had been in place and one of the 

employers had a trained competent person at the time of the incident, the competent person could have recognized the 

hazard posed by the unbraced wall and made the appropriate changes to provide a safe bracing system. Since this 

incident, the masonry subcontractor has trained their employees on proper concrete and masonry wall bracing.
REPORT#: 2014-02 Page 12

Footnotes

1. For maximum height above braces see Table 4.2 for Initial Period requirements or Table A.1 for 

Intermediate Period requirements.

2. For maximum vertical spacing of braces, see Table A.1.

3. Walls shall be considered unreinforced until grout has been in place at least 12 hours.

Figure 1. Wall bracing placement diagram.

(Figure courtesy of MCCA [MCCA 2012].)
REPORT#: 2014-02 Page 13

Figure 2. Wall bracing construction diagram.

(Figure courtesy of MCCA [MCCA 2012].)
REPORT#: 2014-02 Page 14

Recommendation #3: Employers should develop and implement a restricted/limited access zone. 

Discussion: OSHA regulation 29 CFR 1926.706(a) states that a restricted/limited access zone shall be established 

whenever a masonry wall is being constructed. The restricted/limited access zone shall conform to the following: 

• Be established prior to the start of construction of the wall.

• Be equal to the height of the wall to be constructed plus 4 feet and shall run the entire length of the wall.

• Be established on the side of the wall that will be unscaffolded.

• Be restricted to entry by employees actively engaged in constructing the wall. No other employees shall be permitted 

to enter the zone.

• Remain in place until the wall is adequately supported to prevent overturning and to prevent collapse unless the 

height of the wall is over 8 feet, in which case, the restricted/limited access zone shall remain in place until permanent 

supporting elements of the structure are in place [OSHA 1988].

Footnote:

The maximum length of wood bracing as detailed is 16’-0”. This corresponds to a maximum brace 

height of 14’-4” utilizing the maximum brace angle of 1:2 as shown.

Figure 3. Wall bracing construction diagram.

(Figure courtesy of MCCA [MCCA 2012].)
REPORT#: 2014-02 Page 15

Some states have implemented regulations with additional requirements beyond the OSHA requirements. Michigan 

OSHA (MIOSHA) Construction Safety Standard Part 2 – Masonry Wall Bracing (R 408.40206) further defines the 

requirements for restricted/limited access zone. MIOSHA (R 408.40207) requires signage stating “DANGER 

restricted/limited access zone; wall unstable in wind; trained personnel only” on walls over 8 feet in height [MIOSHA 

2010]. These signs must also be posted on the four corners of the restricted/limited access zone, and the signs posted 

around the perimeter must be no more than 25 feet apart (Figure 4). This restricted/limited access zone should be in 

place before construction begins but is not required until the wall is over 8 feet in height. Other states have gone 

beyond the federal OSHA standard and developed limited access zone requirements of their own [OROSHA 2003]. At the 

time of the incident there was not a restricted access zone in place. Additionally, signage should be posted in all 

languages understood by workers on the site. 

Recommendation #4: Employers should train workers on the hazards of working around unsupported masonry walls.

Discussion: As evidenced by this incident, workers not directly involved in erecting masonry walls may not recognize the 

hazards of working near unsupported walls while they are curing. Michigan OSHA established masonry wall rules that 

take a step beyond the federal OSHA regulations. Michigan OSHA requires training for all workers who enter a restricted 

zone of a masonry wall under construction. This training must be provided by a qualified person to any worker who 

enters a restricted zone. The competent person receives additional training on installing, altering, repairing, maintaining, 

or inspecting the wall bracing system and restricted zone. This training must be documented and include names, dates, 

Figure 4. Restricted/limited access zone diagram.

(Figure courtesy of MIOSHA [MIOSHA 2015b].)
REPORT#: 2014-02 Page 16

and signature of the trainer and the latest record of training must be maintained and available during the workshift. 

[MIOSHA 2010]. 

MIOSHA elements of training should include:

The training shall enable an employee to recognize and understand all of the following:

• The nature of hazards involving masonry walls under construction.

• Instruction in the general use and maintenance of wall bracing systems, signage, and restricted zone requirements as 

prescribed in these rules.

• Procedures for monitoring wind speeds.

• Procedures for vacating the restricted zone during windy conditions.

• The nature of hazards involving electrical lines within the restricted zone.

• The nature of hazards involving excavating within the restricted zone.

• Any other pertinent requirements.

Additional training is required in each of the following situations:

• When changes at the worksite present a hazard about which an employee has not been previously trained.

• When changes in the types of wall bracing systems present a hazard for which an employee has not been 

previously trained.

None of the subcontractors had trained their employees on proper concrete and masonry wall bracing. The excavation 

and waterproofing subcontractors had not trained employees on the hazards of working near an unbraced masonry 

wall. Since this incident, the excavation subcontractor has trained their employees on the hazards of working near 

masonry walls. 

Recommendation #5: Employers should assign a competent person trained to monitor wind speeds.

Discussion: The Mason Contractors Association of America (MCAA) recommends employers provide training to those 

employees engaged in masonry activities. Michigan OSHA requires additional training for employees who are designated 

as a competent person provided by a qualified person related to masonry wall construction. 

A competent person, defined by MIOSHA as "“Competent person” means a person who is trained, experienced, and 

capable of identifying existing or potential hazards in surroundings, or under working conditions, that are hazardous or 

dangerous to an employee and who has the authority and knowledge to take prompt corrective measures to eliminate 

the hazards [MIOSHA 2010]. The competent person should understand and be involved in installation, altering, 

maintaining, and inspecting the wall bracing. The competent person must inspect the walls and wall bracing systems at 

the beginning of each shift and after any occurrence that could affect the structural integrity of the wall or wall bracing 

system. The employer shall train all employees entering the restricted/limited access zone of the masonry wall under 

construction. Training shall be on the recognition and avoidance of hazards associated with masonry wall bracing, 

collapse area/restricted/limited access zone, and conditions requiring evacuation. These training records must be 

maintained at the jobsite [MIOSHA 2010].

The MIOSHA competent person training shall enable an employee to recognize hazards associated with the work and 

shall include all of the following topics, as applicable: 

• The nature of hazards involving masonry walls under construction

• Instruction in the general use and maintenance of wall bracing systems, signage, and restricted zone requirements as 
REPORT#: 2014-02 Page 17

prescribed in these rules

• Identifying unsupported masonry walls requiring bracing

• The procedures for installing, altering, repairing, inspecting, and maintaining the wall bracing system being used

• Proper installation and maintenance of a restricted zone and signage

• Procedures for monitoring wind speeds

• Procedures for vacating the restricted zone during windy conditions

• Inspecting the worksite for overhead and underground utilities and other hazards

• Inspecting the worksite for excavations in the restricted zones

• Any other pertinent requirements

The competent person should know the current design period of masonry construction and be able to evacuate the 

restricted/limited access zone if wind speeds meet the evacuation criteria. The hazard associated with a masonry wall 

change as the masonry wall cures over time. Contributing factors include wall thickness, unit weight of masonry, cement 

mortar type, reinforcement, wall height, and stage of construction. There are 2 stages of cure that occur which 

influences the safety of the masonry wall. The first stage is within the first 24 hours of cure time, this is the initial period. 

Masonry walls in the initial period have less strength to sustain wind loads and must be evacuated at lower wind speeds, 

up to 20 mph [MIOSHA 2010; MCCA 2012; NCMA 2014]. The second stage is the intermediate period, once the wall has 

cured 24 hours, it enters the intermediate period and can resist wind speeds up to 35 mph when properly supported 

before evacuation is required [MIOSHA 2010; MCCA 2012; NCMA 2014]. Bracing systems for masonry walls in the 

intermediate period are typically designed for wind speeds of 40 mph allowing a safety factor for the mandatory 

evacuation at 35 mph. Wind speed may be monitored either by using the Beaufort scale or by using wind speed 

measuring device like an anemometer under the OSHA standard. The wind speed should be measured using an 

instrument with a wind speed measurement device +/- 2 mph accuracy [MIOSHA 2010; MCCA 2012]. Wind speed shall 

be monitored by the competent person of each contractor working in the restricted/limited access zone [MIOSHA 2010]. 

MIOSHA recommends the competent person may need to take several wind speed measurements throughout the day if 

conditions warrant it [MIOSHA 2015b]. There are devices that constantly measure wind speed and will alarm when the 

wind speed meets the set limits.

During the day of the incident, wind speeds in the general area of the incident began to increase starting at 8 a.m. from 

11 mph to 20 mph. Wind gusts of 24 mph were recorded at 7:53 a.m. and 28.8 mph at 8:53 a.m. A competent person 

monitoring wind speed at the time of the incident may have noticed the increase in wind gusts and evacuated the 

workers to a safe area [Weather Underground 2013].

Recommendation #6: Employers should schedule work tasks to limit exposure of nonessential workers to hazards 

posed by masonry walls under construction.

Discussion: Prime contractors develop the work plan for a construction job before construction begins. Subcontractors 

are frequently scheduled before the job begins as well. The prime contractor has the opportunity to schedule work tasks 

to limit down-time, re-work, and safety issues. The work activities of the waterproofing contractor could have been 

scheduled before and after the installation of a permanent support system for the masonry wall. The work activities of 

the utility contractor could have been scheduled before the masonry wall was constructed and finalized after the 

permanent support system for the masonry wall was in place.
REPORT#: 2014-02 Page 18

ADDITIONAL RESOURCES

IMI [2013]. IMI Internal bracing design guide for masonry walls under construction. Annapolis, MD: International 

Masonry Institute. 

Lochonic K [2011]. Masonry wall bracing, life safety under windy conditions paramount to updated standard. Masonry 

Edge 6(1):44–46.

DISCLAIMER

Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety 

and Health (NIOSH). In addition, citations to websites external to NIOSH do not constitute NIOSH endorsement of the 

sponsoring organizations or their programs or products. Furthermore, NIOSH is not responsible for the content of these 

websites. All web addresses referenced in this document were accessible as of the publication date.

REFERENCES

Johnson R [2008]. Masonry wall bracing, what goes up, doesn’t have to come down. Structure Magazine, May, 38–41. 

MCCA [2012]. Standard practice for bracing masonry walls under construction. Lombard, IL: Mason Contractors 

Association of America, Council for Masonry Wall Bracing. 

MIOSHA [2010]. Construction Safety Division, Part 2 - Masonry Wall Bracing. Lansing, MI: Michigan Occupational safety 

and Health Administration. 

MIOSHA [2015a]. Masonry wall bracing, CSH fact sheet #028. Lansing, MI: Michigan Occupational safety and Health 

Administration, Construction Safety & Health Division.

MIOSHA [2015b]. Part 2 Masonry wall bracing questions and answers, CSHD Fact Sheet #031. Lansing, MI: Michigan 

Occupational safety and Health Administration, Construction Safety & Health Division.

NCMA [2005]. NCMA TEK 3-4B Bracing concrete masonry walls during construction. Herndon, VA: National Concrete 

Masonry Association. 

NCMA [2014]. NCMA TEK 3-4C Bracing concrete masonry walls under construction. Herndon, VA: National Concrete 

Masonry Association. 

OROSHA [2003]. 437-003-0706 Protection of employees on or near masonry walls. In: Construction, subdivision Q, 

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REPORT#: 2014-02 Page 19

INVESTIGATOR INFORMATION

This investigation was conducted by Jennifer E. Lincoln, Health Scientist, Fatality Investigations Team, Surveillance and 

Field Investigation Branch, Division of Safety Research.

ACKNOWLEDGEMEMENT

The NIOSH FACE Program would like to acknowledge the compliance officer and staff of the Tennessee Department of 

Labor and Workforce Development, the OSHA Directorate of Construction, Engineering Services, and Bryan Wimer, 

NIOSH engineer, for providing assistance and information for this investigation.