Pallet racking glossary.
76 terms explained in plain English — from anchor bolts to working-at-heights regs. CSA A344-17, ANSI MH16.1, rack types, components, and Ontario compliance terms.
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Type to filter every definition live, or jump straight to a letter. 78 terms across racking systems, components, standards, and Ontario safety regulations.
A
Anchor Bolt
A wedge or sleeve anchor that fastens a rack footplate to a concrete slab. Two-per-footplate minimum per CSA A344-17. Embedment depth + slab PSI must match manufacturer spec; never reused on relocation.
ANSI MH16.1
American National Standard for industrial steel storage racks, published by the Rack Manufacturers Institute (RMI). North American spec baseline for selective, push-back, drive-in, and structural racking systems.
AS/RS
Automated Storage and Retrieval System. Combines high-bay racking with computer-controlled cranes/shuttles. Higher cost than VNA but eliminates forklift operator labour for max-density warehouses.
Aisle Width
Clear floor distance between two adjacent rack rows. Standard: 11-13 ft for counterbalance trucks; 5-6 ft for VNA. Narrower = denser storage but slower throughput and tighter operator tolerances. See VNA for narrow-aisle systems.
B
Beam Connector
The locking mechanism that secures a beam end into the upright post. Common types: pin + safety clip (selective), bolted (structural). CSA A344-17 requires safety pins on every beam end.
Beam Pair
Two beams (front + rear) forming one storage level in a selective racking bay. Capacity is rated per beam pair (e.g., 5,000 lb/pair). Multiple pairs stacked vertically per upright frame.
Bill 41
Ontario's Working for Workers Four Act 2024. Raised corporate OHSA fines to $2M. Documented annual rack inspections are part of the employer due-diligence chain it requires.
Box Beam
Closed-tube horizontal beam used in heavier-duty pallet racking. Higher stiffness than step beams but less common in standard selective installs.
Backstop
Vertical safety bar mounted at the rear of selective rack beam pairs to prevent pallets from being pushed off the back. Required by CSA A344-17 wherever the back of the rack is open to a pedestrian aisle.
Bay
One section of selective racking defined by two upright frames and the beams between them. Bays are the unit of pricing, layout, and capacity. Typical bay: 96-108 inches wide.
Beam
Horizontal load-carrying member spanning between two upright frames. Sold by length, profile (step or box), and rated capacity. Two beams form a beam pair (one storage level).
Beam Capacity
Manufacturer-rated load per beam pair, expressed in lbs (e.g., 5,000 lb/pair). Posted on the load-capacity plaque. Exceeding it triggers a red-severity inspection finding under CSA A344-17.
C
Cantilever Rack
Single-sided or double-sided racking with horizontal arms extending from a vertical column. Designed for long, awkward goods (lumber, pipe, steel, sheet stock) where front-beam-style racking doesn't work.
Carton Flow
Inclined-shelf gravity flow system for case picking. Cases load from the back, gravity-flow to the pick face. Different from pallet flow (which moves whole pallets, not cases).
Catwalk
Elevated steel walking surface mounted on top of racking, used for picking or accessing high-bay storage. Requires guardrails per Working at Heights regulations.
Column
Vertical structural member of a cantilever rack. Anchored at the base via a triangular or rectangular footplate. Carries the moment from cantilever arms.
CSA A344-17
Canadian Standards Association User Guide for Steel Storage Racks. Defines design, installation, inspection, and damage classification practices. Every 416 install is aligned to this standard.
Centerline-to-Centerline
Bay-spacing measurement taken from the center of one upright post to the center of the next. Used in stamped drawings and layout plans. Differs from "clear opening" (face-to-face).
Cold Storage Rack
Galvanized or epoxy-coated racking designed for sub-zero freezer or refrigerated warehouse environments. Drive-in is the dominant choice; powder-coat is replaced with corrosion-resistant finishes. See cold-storage industry page.
D
Decking
Surface between or on top of beams. Common: welded-wire mesh deck (for fire-code compliance + smaller items), solid steel deck (sheet goods), or no deck (pallets only).
Deflection
Vertical or horizontal sag of a loaded beam. CSA A344-17 limits deflection to 1/180 of span. Excessive deflection triggers a red-severity finding on inspection.
Drive-In Rack
High-density rack lane (LIFO) where the forklift drives INTO the lane to load/retrieve pallets. No front beam; pallets sit on side rails. Best for same-SKU bulk + cold storage.
Drive-Thru Rack
Drive-in variant with both ends open (FIFO), allowing load-in one side, pick from the other. Less common; replaced by pallet flow in most modern applications.
Diagonal Brace
Angled steel member between the two posts of an upright frame. Triangulates the frame and resists lateral forklift impact + seismic loads. Bent or missing braces are a high-severity inspection finding.
Double-Deep Rack
Selective racking arranged in two-deep rows, picked with a double-reach forklift. Roughly 30% denser than single-deep selective; loses ~50% selectivity.
E
Engineered Stamp (P.Eng)
A Professional Engineer's seal on racking drawings. Required by most GTA municipalities for systems over 25 ft tall, mezzanine-mounted, or in seismic-rated buildings.
End Frame
The first or last upright frame in a row of selective racking. Often has extra protection (column guards, end-of-aisle barriers) because it's most exposed to forklift impact.
F
FIFO
First-In First-Out. Inventory rotation where the oldest pallet is picked first. Achieved with pallet flow racking. Critical for date-sensitive inventory (food, beverage, pharma).
Footplate
Steel plate welded to the base of each upright post. Distributes load to the slab and accepts anchor bolts. CSA A344-17 requires footplates on every frame.
Frame (Upright Frame)
Two vertical posts joined by horizontal stiffeners and diagonal braces. Defines rack height + load capacity. Sold by depth (typically 36, 42, 48, 60 inches) and height (8 ft to 45 ft).
Fire Protection
Sprinkler design + flue-space requirements that govern rack layout in warehouses. In-rack sprinklers may be required above certain heights (NFPA 13). Coordinate rack layout with the fire-protection engineer early.
Flue Space
Required clearance between back-to-back pallets (transverse flue) and between pallets in a row (longitudinal flue) so sprinkler water reaches lower levels. Typically 3-6 inches per NFPA 13.
Forklift
Powered industrial truck used to move pallets in and out of racking. Type determines aisle width: counterbalance (11-13 ft), reach (8-9 ft), VNA turret (5-6 ft).
G
Galvanized
Steel coated in zinc for corrosion resistance. Required for outdoor cantilever, cold storage drive-in, and food/beverage operations where powder-coat would chip and contaminate.
Gauge
Steel thickness, measured inversely (lower gauge = thicker steel). Common upright gauges: 14ga (standard duty), 13ga (heavy duty), 11ga (structural).
Guide Rail
Floor-mounted steel angle or wire-buried inductive guide that keeps a forklift centered in a narrow aisle (VNA). Floor rails are mechanical; wire guides use the forklift's antenna.
Gravity Flow
Storage system using inclined rollers or wheels so pallets/cartons advance toward the pick face under gravity. Eliminates labour for product rotation. Used in pallet flow and carton flow racks.
H
Hot-Rolled Steel
Steel formed at high temperature (>1700°F), producing thicker, more impact-tolerant sections than cold-rolled steel. Hot-rolled is standard for structural racking; cold-rolled (roll-formed) for selective.
I
Impact Guard
Steel pillar protector at the base of an upright frame. Required at lane entries on drive-in racking and recommended at all aisle ends. Absorbs forklift impact instead of the rack frame.
In-Rack Sprinkler
Sprinkler heads installed inside the racking (not at ceiling) to suppress fires deep inside high-density storage. Required by NFPA 13 above certain pallet-load heights or for plastic-contained goods.
K
Kickplate
Horizontal toe-board at the base of an elevated platform, mezzanine, or catwalk that prevents tools/parts from being kicked off. Required per Working at Heights regulations.
L
Lane
Single aisle of pallet positions in push-back, drive-in, or pallet flow systems. Width = pallet width + clearance. Depth = number of pallets deep × pallet length.
LIFO
Last-In First-Out. Inventory ordering where the most recently loaded pallet is picked first. Push-back and drive-in racking are LIFO systems.
Load Capacity Plaque
Required CSA A344-17 placard at the end of every aisle showing rated capacity per beam pair + per frame. Permanent, weather-resistant. Updated whenever beam levels change.
Load Distribution
How the rated weight is positioned across a beam pair. Uniformly distributed is the standard rating; point loads or unbalanced loads reduce effective capacity by 30-50%.
M
Mezzanine
Elevated steel platform within a warehouse, often supporting catwalks, offices, or secondary storage. Subject to OHSA + OBC + sometimes PSR review.
MLITSD
Ontario Ministry of Labour, Immigration, Training and Skills Development. Enforces OHSA. Our inspection reports are formatted for MLITSD inspector review.
O
OHSA
Ontario's Occupational Health and Safety Act. The primary workplace safety legislation that governs warehouse rack maintenance and inspection requirements.
OSHA
U.S. Occupational Safety and Health Administration. Equivalent regulator to Ontario's MLITSD. References to "OSHA" in spec sheets typically apply only to U.S. operations; Canadian sites follow OHSA + CSA A344-17.
P
Pallet Flow Rack
Gravity-flow system with inclined rollers. Pallets load at the high end, gravity-flow toward the pick face. FIFO. Common in food, beverage, pharma operations.
Pick Face
The vertical face of a rack where pallets are picked from. Selective racking: every level is a pick face. Drive-in: only the front position is a pick face.
Powder Coat
Sprayed-on dry powder finish baked onto the steel. Standard for indoor racking. Common colors: orange (Mecalux), blue (Ridg-U-Rak), or custom.
PSR
Pre-Start Health and Safety Review. Required under Ontario Regulation 851 Section 7 before certain industrial equipment goes into service. Coordinated by P.Eng + Occupational Hygienist.
Push-Back Rack
Multi-deep racking (2-6 deep) with inclined rails + nested carts. Forklift pushes new pallets back; gravity flows them forward. LIFO. +90% storage density vs selective.
Pallet Stop
Steel angle or bar at the discharge end of a pallet flow or push-back lane that holds the front pallet in place against gravity. Removed by the picker to extract the pallet.
Pinch Point
Location where a forklift, pallet, or moving rack component (push-back cart) can trap a body part. Identified on inspection reports; managed via guards, training, and signage.
R
RMI
Rack Manufacturers Institute. The North American trade association that publishes ANSI MH16.1 — the spec we cross-reference on every install.
R-Mark
Voluntary certification mark from the Rack Manufacturers Institute showing that a rack manufacturer's systems meet ANSI MH16.1 design standards. R-Mark systems are accepted in most permit jurisdictions without re-engineering.
Roll-Formed Rack
Cold-rolled steel rack manufactured by passing flat steel through forming rollers (vs hot-rolled structural). Lighter, lower-cost, faster lead time. Standard for selective racking.
Row Spacer
Short horizontal steel connector that ties back-to-back rows of selective racking together at the upright frames. Maintains transverse flue space and stiffens the back-to-back run.
S
Selective Racking
The industry-standard racking system — single-deep, 100% selectivity, every pallet directly accessible. 3-5 day lead times. Beam levels are field-adjustable in 2-inch increments.
Slab
The concrete floor on which racking is anchored. Minimum thickness + PSI rating must meet manufacturer spec. Standard: 6" minimum, 3,500 PSI for selective; 8"+ 4,000 PSI for VNA/structural.
Span
The horizontal distance between two upright frames in a bay (typically 96", 108", or 120"). Larger spans reduce frame count but require heavier beams.
Speed Controller
Hydraulic damper in push-back and pallet flow systems that prevents runaway pallet flow. Maintains steady cart/pallet speed regardless of load weight.
Stamped Drawings
Engineering drawings sealed by a P.Eng. Required by most GTA municipalities for permits on racking projects above certain height/load thresholds.
Step Beam
Standard horizontal beam with a step profile that supports wire decking + pallets. Lighter and cheaper than structural C-beam. Default on selective racking.
Structural Rack
Hot-rolled, bolted-construction racking (vs roll-formed selective). Heavier, more impact-resistant, longer lead times (2-3 weeks). Common in cold storage and high-traffic facilities.
Seismic Zone
Geographic seismic-hazard rating that governs rack engineering. GTA = Site Class C/D, moderate seismic. CSA A344-17 + the National Building Code dictate brace patterns + anchor counts by zone.
Shim
Thin steel plate placed between a footplate and the slab to level uneven concrete. Manufacturer-spec'd thickness limits apply (typically 1/2 inch max stack); excess shimming requires re-engineering.
SKU
Stock Keeping Unit. A single product variant tracked in inventory. SKU count + velocity per SKU drives the choice between selective (high SKU count) and drive-in/push-back (low SKU count, high volume).
T
Teardrop
The most common upright post profile in North American selective racking. Tear-shaped holes accept beam-end connectors. Compatible across major manufacturers.
Throughput
Number of pallet moves per hour (or per shift) a racking system supports. Selective = highest throughput; drive-in = lowest (LIFO penalty).
Tie Beam
Cross-beam at the top of drive-in racking that ties all frames together. Distributes lateral load and prevents racking sway under dynamic forklift loading.
U
Upright
Vertical post of an upright frame. Sold by gauge (14ga to 11ga), depth (36-60 in), and height (8 ft to 45 ft). Two uprights joined by braces = one upright frame.
V
VNA
Very-Narrow-Aisle. Racking with 5-6 ft aisles (vs 10-12 ft standard) and forklifts that operate in that space. Max-cube system; common above 30 ft tall.
W
Wire Deck
Welded-wire mesh shelf on top of beams. Required where smaller-than-pallet items are stored. Also improves fire sprinkler effectiveness vs solid deck.
Working at Heights
Ontario MOL training requirement for any work over 3 metres. Every 416 installer carries current certification. Required for racking taller than ~10 ft.
WSIB
Workplace Safety and Insurance Board. Ontario's workers' compensation system. 416 Industrial is WSIB-insured — verifiable via the WSIB clearance certificate.
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