Split-Faced Concrete Unit Masonry AHA (Activity Hazard Analysis / Job Hazard Analysis)

Updated 2026-06-23

A Split-Faced Concrete Unit Masonry AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan that keeps the crew building split-faced concrete unit masonry safe from the sharp rough split face and heavy handling, from the masonry-wall stability and collapse, and around the cutting silica and mortar contact. Split-faced concrete unit masonry lays concrete block with a rough, split (fractured) face — combining the sharp-rough-split-face and heavy-handling hazard, the masonry-wall-stability and collapse hazard, and the cutting-silica and mortar-contact hazard. This guide walks through building a Split-Faced Concrete Unit Masonry AHA that names the sharp-rough- split-face/heavy-handling, masonry-wall-stability/collapse, and cutting-silica/mortar-contact hazards and assigns the handling, stability, and silica/contact controls that hold up in the field.

Why split-faced concrete unit masonry needs its own AHA

Split-faced concrete unit masonry is the construction of walls using split-faced concrete masonry units — architectural block manufactured by splitting (fracturing) the block to create a rough, textured, stone-like face exposed as the finished architectural surface. This continues the architectural-CMU cluster. The defining feature is the split (fractured) face: the manufacturing split leaves a rough, sharp, jagged face with sharp aggregate and edges (a laceration/abrasion hazard when handling, more pronounced than smoother faces), on top of the standard concrete-block hazards (heavy handling, wall stability, silica, mortar). The hazards combine the sharp-rough-split-face and heavy-handling (the block has a rough, sharp, split (fractured) face and is heavy (concrete) — the sharp-face hazard (the split face is rough and sharp, with sharp aggregate and jagged edges — a laceration/abrasion hazard when handling) and the heavy-handling/ergonomic hazard), the masonry-wall-stability and collapse (building up the block wall — the wall-stability/collapse hazard (unbraced fresh masonry walls collapse, especially under wind)), the cutting-silica and mortar-contact (cutting the concrete block (silica) and the caustic mortar (cement burns)), and the scaffold-access/falling-material. The sharp-rough-split-face/heavy- handling and the masonry-wall-stability/collapse justify a dedicated AHA.

Breaking split-faced concrete unit masonry into steps

The steps for a Split-Faced Concrete Unit Masonry AHA follow the laying:

• Set up scaffold access and material staging (block within reach)
• Mix and spread the mortar (caustic contact)
• Lay the split-faced block in courses (sharp face, heavy handling)
• Brace the wall as it is built (wall stability)
• Cut block as required (silica control)
• Manage the sharp-face, stability, and silica hazards
• Point, clean, and protect the split face
• Complete

Each step carries a hazard, and the sharp-rough-split-face/heavy-handling, the masonry-wall-stability/collapse, and the cutting-silica/mortar-contact are where the most significant risks concentrate.

The hazards step by step

Sharp-rough-split-face and heavy-handling

The block has a rough, sharp, split (fractured) face and is heavy (concrete) — the sharp-face hazard (the split face is rough and sharp, with sharp aggregate and jagged edges — a laceration/abrasion hazard when handling) and the heavy-handling/ergonomic hazard. The controls are hand protection against the sharp split face (the split (fractured) face is rough, sharp, and jagged, with sharp exposed aggregate and edges — cut-resistant gloves, since handling split-faced block repeatedly cuts and abrades unprotected hands more than smoother block), managing the heavy-block handling and ergonomics (heavy concrete block — staging within reach, good work height, mechanical/team lifting, pacing, rotation), and the sharp-face/handling controls. The sharp-rough-split-face/ heavy-handling is the primary defining hazard — the split face is sharp and the block is heavy. (These follow the sharp-material-handling fundamentals.)

Masonry-wall-stability and collapse

Building up the block wall — the wall-stability/collapse hazard (unbraced fresh masonry walls collapse, especially under wind). The controls are bracing masonry walls during construction (unbraced fresh masonry walls collapse under wind — bracing per the requirements, exclusion zones behind a wall being built), and the wall-stability controls. The masonry-wall-stability/collapse is a defining hazard — unbraced fresh block walls collapse. (These follow the masonry-wall-bracing fundamentals.)

Cutting-silica and mortar-contact

Cutting the concrete block (silica) and the caustic mortar (cement burns). The controls are silica control for cutting concrete block (concrete block is high in silica — cutting generates respirable silica — wet cutting, dust extraction, respiratory protection), preventing skin contact with the caustic mortar (gloves, skin protection), and the silica/contact controls. The cutting-silica/mortar-contact is a defining hazard. (These follow the silica and cement-contact fundamentals.)

Scaffold-access/falling-material

The scaffold access and falling material (building from scaffolds, falling heavy block/tools) carries the access/ falling-object hazard. The controls are safe scaffold access (fall protection), falling-object protection (toe boards, controlled access below), and the access/falling controls. (These follow the scaffold and falling-object fundamentals.)

A simple Split-Faced Concrete Unit Masonry AHA structure

Sharp-face/heavy handling control and wall-stability/silica safety

A Split-Faced Concrete Unit Masonry AHA centers on sharp-face/heavy handling control and wall-stability/silica safety. The sharp-face/heavy handling control addresses the sharp split face and heavy block — controlled by hand protection against the sharp split face (cut-resistant gloves, since the fractured face cuts unprotected hands) and managing the heavy-block handling and ergonomics. The wall-stability/silica safety addresses the wall and the cutting — controlled by bracing masonry walls during construction (unbraced fresh block walls collapse under wind) and block-cutting silica control, plus caustic-mortar contact protection. And the scaffold access and falling material get access and falling-object controls. An AHA built on sharp-face/heavy handling control and wall-stability/silica safety, with access controls, addresses the hazards that define split-faced concrete unit masonry.

From the field: what actually goes wrong

In fourteen years across federal, heavy civil, and industrial projects, split-faced concrete unit masonry lays concrete block with a rough, split (fractured) face, and it continues the architectural-CMU cluster with the distinctive hazard of the sharp split face. The sharp-rough-split-face and heavy-handling hazard is the primary defining concern — split-faced block is manufactured by splitting (fracturing) the block to create the rough, stone-like textured face, and that fractured face is genuinely rough and sharp: it has sharp exposed aggregate, jagged edges, and an abrasive texture, so handling split-faced block repeatedly cuts and abrades unprotected hands more than smoother block does (masons laying split-faced block all day get cut and abraded hands without good hand protection), making cut-resistant gloves an important control, more so than for smooth block. And the block is heavy (concrete), so the significant manual-handling and ergonomic hazard applies as with all block (staging within reach, good work height, mechanical and team lifting, pacing, rotation). The sharp fractured face combined with the weight is what defines split-faced block handling.

The masonry-wall-stability/collapse and the cutting-silica/mortar-contact are the other defining hazards, and they are the shared unit-masonry themes. On the projects I have run, building up the split-faced block wall brings the same defining masonry-construction hazard — a freshly laid, unbraced masonry wall can collapse, especially under wind, so bracing masonry walls during construction (per the requirements, with exclusion zones) is critical. And the cutting-silica hazard (concrete block is high in silica — cutting generates respirable silica, controlled by wet cutting, dust extraction, and respiratory protection) and the caustic-mortar contact (cement burns — gloves and skin protection) are the familiar masonry material hazards. The scaffold access and the falling-material hazard round it out. The AHA built on sharp-face/heavy handling control and wall-stability/ silica safety is the one that protects the split-faced-block crew.

The bottom line

A Split-Faced Concrete Unit Masonry AHA names the sharp-rough-split-face/heavy-handling, the masonry-wall- stability/collapse, and the cutting-silica/mortar-contact hazards with specific controls — hand protection against the sharp fractured face (it cuts and abrades unprotected hands) with heavy-block handling management, bracing masonry walls during construction (unbraced fresh walls collapse under wind), and block-cutting silica control with caustic-mortar contact protection. The sharp-face/heavy handling control and the wall-stability/silica safety are the defining concerns. The AHA that manages both is the one that protects the crew.

Frequently asked questions

Why is the split face a sharper handling hazard?

Split-faced block is manufactured by splitting (fracturing) the block to create the rough, stone-like textured face, and that fractured face is genuinely rough and sharp — with sharp exposed aggregate, jagged edges, and an abrasive texture — so handling split-faced block repeatedly cuts and abrades unprotected hands more than smoother block does (masons laying it all day get cut and abraded hands without good hand protection). Controls are hand protection against the sharp split face (cut-resistant gloves), managing the heavy-block handling and ergonomics (staging within reach, good work height, mechanical/team lifting, pacing, rotation), and the sharp-face/handling controls.

Why is masonry-wall stability a defining hazard?

Building up the split-faced block wall brings the same defining masonry-construction hazard as all unit masonry — a freshly laid, unbraced masonry wall can collapse, especially under wind. Controls are bracing masonry walls during construction (per the requirements limiting unbraced masonry wall height, exclusion zones behind a wall being built), and the wall-stability controls.

What silica and mortar hazards apply?

Concrete block is high in silica, so cutting it generates respirable silica, and the caustic mortar causes cement burns from skin contact. Controls are silica control for cutting concrete block (wet cutting, dust extraction, respiratory protection), preventing skin contact with the caustic mortar (gloves, skin protection), and the silica/contact controls.

What is split-faced concrete unit masonry?

Split-faced concrete unit masonry is the construction of walls using split-faced concrete masonry units — architectural block manufactured by splitting (fracturing) the block to create a rough, textured, stone-like face exposed as the finished architectural surface. Because the split face is sharp (laceration/abrasion) and the block is heavy, unbraced fresh masonry walls can collapse, and cutting block generates silica with caustic mortar, those hazards apply.

Related AHAs and JHAs

• Architectural Concrete Unit Masonry AHA — the architectural-CMU fundamentals
• Fluted Concrete Unit Masonry AHA — the related fluted variant
• Concrete Unit Masonry AHA — the standard concrete unit masonry
• Masonry and Block Wall Construction JHA — the block-wall-construction fundamentals

Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.