Glossary: Lifting Equipment Terms
Plain-language definitions of the terms used in portable aluminum lifting equipment — cranes, components, standards, and operations. Where relevant, entries link to full Reference pages or Guides.
Jump to: A · B · C · D · E · F · G · H · I · L · M · O · P · R · S · T · W
A
6061-T6 Aluminum
A heat-treated aluminum alloy commonly used in structural applications including lifting equipment. The “-T6” refers to the heat treatment (solution heat-treated and artificially aged) that produces the alloy’s structural strength. 6061-T6 has well-characterized mechanical properties — typical mill-certified yield ~40 ksi, with an Aluminum Design Manual (ADM) design minimum Fty = 35 ksi, and tensile strength around 45,000 psi — making it suitable for load-bearing aluminum structures. It is the standard alloy for portable aluminum gantry and davit cranes, and for Eagle Beam lifting beams.
ADM (Aluminum Design Manual)
The Aluminum Design Manual, published by The Aluminum Association — the primary US design specification for aluminum structures, covering allowable stresses, buckling, and connections. The ADM is the aluminum-structure equivalent of the steel design codes, and eme designs its aluminum structures to the ADM.
A-Frame Gantry Crane
A gantry crane configuration with legs that form an “A” shape when viewed from the end. The A-frame shape provides inherent lateral stability — the wider base prevents tipping under off-center loads. Portable aluminum gantry cranes, including the full eme gantry line, use A-frame construction.
ASME
The American Society of Mechanical Engineers. A professional engineering organization that publishes voluntary consensus standards, including the B30 series that governs cranes, hoists, rigging hardware, and below-the-hook lifting devices. ASME standards are referenced by OSHA regulations and widely accepted across North American industry as the design and safety baseline for lifting equipment. ASME standards are not third-party certifications — manufacturers design and build to the standards and self-declare compliance.
ASME B30.17
The American safety standard for cranes and monorails. B30.17 specifies design, construction, installation, operation, inspection, testing, and maintenance requirements for equipment in its scope. Its comprehensive single-girder crane provisions apply to portable aluminum gantry cranes — eme designs its top-running single-girder box-beam gantry cranes to B30.17. Full reference: What is ASME B30.17? →
ASME B30.2
The ASME safety standard for top-running bridge and gantry cranes equipped with top-running trolley hoists. Its scope assumes a fixed runway with dedicated rails — that is, permanent installations. B30.2 does NOT apply to portable, caster-mounted gantries like eme’s, which have no runway; eme’s portable gantries are designed to ASME B30.17 instead. B30.2 references crane design specifications such as CMAA 70 for structural design.
ASME BTH-1
The American design standard for below-the-hook lifting devices — spreader beams, lifting beams, plate clamps, magnets, vacuum lifters, and similar attachments used between a crane’s load hook and the load. BTH-1 specifies design factors (2:1 for Category A, 3:1 for Category B), service classes for fatigue life, structural design rules, and documentation requirements. eme’s Eagle Beam is designed to BTH-1 Category B with a 3:1 design factor. Full reference: What is ASME BTH-1? →
AWS D1.2
Structural Welding Code — Aluminum. The American Welding Society code governing aluminum weld procedures and welder qualification — the procedural code aluminum welds are produced to. AWS D1.2 is the US counterpart to the Canadian CSA W59.2.
B
Below-the-Hook Lifting Device
A device attached between a crane’s load hook and the load being lifted. Examples include spreader beams, lifting beams, plate clamps, magnets, vacuum lifters, coil grabs, and custom attachments. Below-the-hook devices are covered by ASME BTH-1 (design) and ASME B30.20 (operation). The crane, the hook, and the slings are not below-the-hook devices — they have separate standards. In the eme catalog, the Eagle Beam is the only below-the-hook lifting device manufactured by the company.
C
Caster
The wheel assembly on a portable gantry crane’s legs. Casters carry the crane’s weight plus any rolled load, provide steering and mobility, and include brakes in most industrial configurations. Caster selection matters for a gantry’s rolling characteristics and rated capacity during rolling — different surface conditions (shop floor, pressure-sensitive surfaces, outdoor) may call for different caster types (polyurethane, pneumatic, steel).
Category A (BTH-1)
A classification under ASME BTH-1 for below-the-hook lifting devices in less severe service. Category A uses a 2:1 design factor on yield stress of load-bearing members. Applies to devices in controlled environments with predictable loading, skilled dedicated operators, minimal shock loading, and limited frequency of use — typically fixed-facility applications.
Category B (BTH-1)
A classification under ASME BTH-1 for below-the-hook lifting devices in more severe service. Category B uses a 3:1 design factor on yield stress — the more conservative of the two categories. Applies to devices in variable service: higher frequency, multiple operators, variable loading, potential shock loading. Portable industrial lifting equipment almost always uses Category B. eme’s Eagle Beam is Category B.
CE Marking
The conformity mark that indicates a product complies with applicable European Union directives and can be placed on the EU market. For lifting equipment, CE marking evidences compliance with the Machinery Directive (2006/42/EC) and relevant harmonized standards (EN 13001, EN 14492, etc.). CE marking is a European market requirement; it is not a substitute for ASME or OSHA compliance in the North American market, though it may be recognized alongside them.
Certificate of Test
A document produced by a manufacturer (or independent testing organization) certifying that a specific lifting unit has passed the required load test. Typically specifies the rated capacity, the test load (often 125% of rated capacity for portable industrial equipment), the testing method (load cell verification), and the date and facility of the test. eme ships a Certificate of Test with every gantry, davit, and Eagle Beam.
Clear Span
The horizontal distance between the inside edges of a gantry crane’s legs — the working space in which the load operates. Clear span determines the maximum horizontal load footprint the crane can accommodate, including allowance for the trolley, rigging, rotation, and operator clearance. Often abbreviated “clear span” or “inside dimension.”
CMAA 70
The Crane Manufacturers Association of America specification for top-running bridge and gantry cranes. CMAA 70 is a design specification — covering crane structural design, service classes, and load combinations — that ASME B30.2 references for the structural design of cranes in its scope.
CSA (Canadian Standards Association)
CSA Group (often referred to as CSA) is a Canadian standards-development organization. CSA publishes standards across industries including crane safety (CSA B167), structural aluminum design (CSA S157), and fusion welding certification (CSA W47.1 for steel; CSA W47.2 for aluminum). CSA standards apply in the Canadian market; in the US, they are recognized as quality markers but are not mandatory compliance requirements.
CSA B167
The Canadian standard for crane safety, covering overhead, mobile, and portable cranes. Serves a similar function to ASME B30.17 in the United States. Required for compliance in Canadian workplaces under provincial occupational health and safety frameworks.
CSA S157
The Canadian standard “Strength Design in Aluminum” — the design code for structural aluminum load-bearing members. Relevant for aluminum lifting equipment because the crane itself is a structural aluminum assembly. Covers material properties, allowable stresses, connection design, and related engineering practice. Applies to the Canadian market.
CSA W47.1 and W47.2
Two Canadian welding certification standards administered by the Canadian Welding Bureau (CWB). W47.1 covers “Certification of Companies for Fusion Welding of Steel.” W47.2 covers “Certification of Companies for Fusion Welding of Aluminum.” The two standards are structurally similar but address different base metals, different filler alloys, and different welder qualification requirements. A manufacturer producing aluminum lifting equipment requires W47.2 (not W47.1). Full reference: What is CSA W47.2? →
CSA W59.2
The Canadian Standards Association code “Welded Aluminum Construction” — governing aluminum weld procedure qualification and acceptance criteria. CSA W59.2 is the Canadian counterpart to the American AWS D1.2, providing the procedural and acceptance rules for aluminum welds.
CWB (Canadian Welding Bureau)
A Canadian non-profit certification body that administers welding certifications under CSA W47.1 (steel) and W47.2 (aluminum). The CWB evaluates welding procedures, welder qualifications, welding supervision, and quality-control systems, and issues certifications to companies that meet the requirements. The CWB maintains a public directory at cwbgroup.org that allows verification of certified companies, personnel, and welding consumables.
D
Davit Crane
A single-mast or single-arm crane, typically mounted to a base socket, with the hoist at the end of a horizontal arm that rotates around the vertical mast. The load moves in an arc around the davit’s vertical axis rather than along a beam. Portable aluminum davits are typically rated up to around 2,200 lb and are designed with a design factor on yield stress well in excess of the proof-test load. Davit cranes are particularly suited to confined-space, manhole, rooftop, and fixed-location lifting where a two-legged gantry cannot set up. Full guide: Gantry vs. Davit →
Dead Load
The static weight of the crane itself, plus any permanently attached equipment. Distinct from the live load (the variable load being lifted). Dead load is considered in the crane’s structural design but is not what the “rated capacity” refers to — rated capacity addresses the live-load lifting capacity of the crane.
Design Factor
A multiplier applied to a structural member’s yield or ultimate stress that establishes the safety margin between the rated load and the material’s failure point. A 3:1 design factor on yield stress means the load-bearing member is engineered to handle three times the rated load before reaching yield. BTH-1 Category A uses 2:1; Category B uses 3:1. Sometimes called “safety factor” — the terms are used interchangeably in common usage, though “design factor” is the more precise term.
Dynamic Load
The load on a lifting structure resulting from motion — starting, stopping, swinging, impact — in addition to the static weight of the load. Dynamic loading can exceed static loading by 20-50% or more in rough handling. The design factor in lifting equipment standards provides margin to handle dynamic loading within the rated capacity.
E
Engineer-Stamped Drawing
A structural drawing reviewed and certified by a licensed professional engineer. For lifting equipment, an engineer-stamped drawing shows the load-bearing members, design factors, material specifications, and structural details. Engineer-stamped drawings are part of the documentation a manufacturer provides with certified equipment; they are required in some jurisdictions and expected by safety officers, insurers, and procurement teams. eme ships an engineer-stamped drawing with every unit.
F
Fusion Welding
A category of welding processes in which two base metals are melted together (usually with a filler metal) to form a single fused joint. Common fusion welding processes include GMAW (gas metal arc welding / MIG), GTAW (gas tungsten arc welding / TIG), and SMAW (shielded metal arc welding / stick). Aluminum structural lifting equipment is typically fusion-welded using GMAW or GTAW with aluminum-specific filler alloys (4043 or 5356). CSA W47.2 certifies companies performing fusion welding of aluminum.
G
Gantry Crane
A freestanding crane with two legs (or occasionally four), a main beam across the top, and a trolley-mounted hoist that travels along the beam. Gantry cranes can be fixed (running on rails) or portable (rolling on casters). Portable aluminum gantry cranes typically cover 1,100 lb to 22,000 lb rated capacity. eme’s portable aluminum gantries are top-running, single-girder, box-beam cranes — the surround-beam trolley rides on top of the box beam — and are designed to ASME B30.17. Full guide: How to Choose a Portable Gantry Crane →
Grade L9 Fastener
A high-strength bolt classification commonly used in structural lifting applications, formally SAE J429 Grade 9 (Grade L9). Grade L9 fasteners have a minimum tensile strength of 180,000 psi (180 ksi) and a 145 ksi proof load — meaningfully higher than common Grade 5 (120 ksi) or Grade 8 (150 ksi) bolts. This higher strength allows smaller fasteners to handle heavier structural loads, with improved fatigue and load-handling characteristics. Used in all-bolted aluminum lifting constructions — including the eme Eagle Beam — where welds are not used in the load-bearing structure.
Grip Eye
A pump-lifting attachment used to hook a submersible pump at the bottom of a well or lift station and extract it in a single lift motion. The Grip Eye slides down a chain attached to the pump and hooks into a link at the bottom, allowing the crane or davit to pull the pump vertically. An alternative to “index lifting” (step-by-step extraction). eme offers the Grip Eye as an accessory for wastewater and submersible pump service applications.
H
HAZ (Heat-Affected Zone)
The weld-adjacent region of an aluminum structure where welding heat reduces strength. For 6061-T6, yield in the HAZ drops to roughly Fty ≈ 14 ksi — about a 65% reduction from unwelded T6. The HAZ is the most important aluminum-specific design consideration for welded structures, and it must be accounted for wherever a load-bearing aluminum member is welded.
Hoist
The powered (or manual) lifting mechanism that raises and lowers the load on a crane. A hoist typically consists of a lifting motor or manual drive, a chain or wire rope, a load block with a hook, and operator controls. Hoists can be manual (chain hoist), electric, or pneumatic, and are rated to specific capacities that must match or exceed the application. The hoist is distinct from the crane that supports it — the same crane can often accept different hoists.
Hoist Overhead
The vertical space the hoist itself occupies between the crane’s main beam and the load hook. Hoist overhead reduces the effective lift height available for the load and must be accounted for when specifying a gantry crane. Overhead varies with hoist type (manual vs. electric) and rated capacity — higher-capacity hoists generally require more overhead. See also: Lift Height.
I
Index Lifting
A multi-step pump extraction method in which a submersible pump is lifted incrementally — raising the chain one short increment at a time, re-rigging, lifting again — rather than in a single smooth motion. Index lifting is sometimes necessary when a crane’s lift height is insufficient for a single-pass lift from the bottom of a deep well. Alternatives like the Grip Eye allow single-pass extraction, reducing setup complexity and lift time.
L
Lift Height
The vertical distance from the floor (or mounting surface) to the underside of a crane’s main beam, at the crane’s maximum height setting. Effective working lift height is reduced by the hoist overhead, the sling or chain length, and the margin needed to rotate or position the load. A crane’s advertised lift height is not the full working space — always subtract hoist overhead and rigging length when specifying.
Lifting Beam
A below-the-hook device consisting of a beam with a lifting eye or hook at one or more points along its length, used to pick up a load at distributed points. Distinguished from a spreader beam (which uses slings from each end to the load). A lifting beam transfers load vertically through the beam’s bending strength. Designed to ASME BTH-1. eme’s Eagle Beam is a lifting beam.
Live Load
The variable load being lifted by a crane — the pump, motor, machinery, or equipment whose weight varies from lift to lift. Distinct from the dead load (the self-weight of the crane). Rated capacity refers to the live load the crane is engineered to handle, not including the crane’s own weight.
Load Cell
A transducer that measures the force applied to a lifting mechanism, producing a calibrated electrical signal proportional to the load. Used in proof-load testing to verify a lifting unit’s rated capacity. eme load-tests every gantry, davit, and Eagle Beam to 125% of rated capacity using a load cell, and includes the verified test result on the Certificate of Test.
Load Test
A test in which a lifting device is loaded to a specified percentage of its rated capacity to verify structural and operational integrity. eme applies a two-test framework: a per-unit production proof test at 125% of rated capacity on every crane and davit before shipment (recorded on the Certificate of Test), and a per-design qualification test — a 150% proof-load test that almost all eme designs additionally pass, performed once during product approval and documented on the P.Eng-stamped drawing. Load tests are conducted at the manufacturing stage (before shipment), after significant repair, and on periodic schedules during the equipment’s service life per ASME standards.
LOLER
The United Kingdom’s Lifting Operations and Lifting Equipment Regulations 1998 — the regulation governing lifting activities in the UK. LOLER requires periodic thorough examination of lifting equipment, operator competence verification, and risk assessment of lifts. The UK equivalent of OSHA’s crane-operation regulations, with different specific requirements. Operated under the UK Health and Safety Executive (HSE).
M
Main Beam
The horizontal structural member of a gantry crane that supports the trolley and hoist. The main beam spans between the two legs (on an A-frame gantry) and carries the load as bending stress. On eme’s top-running single-girder box-beam gantries, the surround-beam trolley rides on top of the main beam. The crane is covered by the crane standard (ASME B30.17), not BTH-1 — BTH-1 applies only to below-the-hook lifting attachments. eme gantries are load-tested to 125% of rated capacity before shipment, with a Certificate of Test.
O
OSHA
The Occupational Safety and Health Administration — the US federal agency that regulates workplace safety. OSHA issues regulations (29 CFR 1910 for general industry; 29 CFR 1926 for construction) that govern crane safety, operator training, inspection, and related practices. OSHA regulations frequently reference ASME consensus standards as the accepted practice, making ASME compliance effectively mandatory for lifting equipment in US workplaces.
P
Pick Point
A specific location on a load or on a lifting device where the crane attaches. Lifting beams and spreader beams typically have multiple pick points (often adjustable) to match the load’s geometry. Proper pick point selection balances the load and keeps the hoist centered above the center of gravity.
Pneumatic Caster
A caster type with an air-filled rubber tire, used on portable gantry cranes for operations on rough or pressure-sensitive surfaces. Pneumatic casters provide softer rolling characteristics than solid polyurethane casters and distribute the load more gently on substrates that could be damaged by concentrated caster loads. eme offers pneumatic casters as an option on gantry models up to 4,400 lb capacity.
Portable Gantry Crane
A gantry crane designed to roll on casters rather than run on fixed rails, allowing the whole crane to be repositioned across a workspace or jobsite. Distinguished from fixed gantry cranes (permanent installations on rails) and overhead bridge cranes (fixed to building structure). Portable aluminum gantries typically range from 1,100 lb to 22,000 lb rated capacity.
Proof Load
A test load applied to a lifting device that exceeds the rated capacity by a specified percentage. eme uses two distinct proof loads: a per-unit production test at 125% of rated capacity, applied to every crane and davit during manufacturing and recorded on the Certificate of Test; and a per-design qualification test — a 150% proof-load test that almost all eme designs additionally pass, performed once during product approval on the P.Eng-stamped drawing. OSHA 1910.179(k)(2) caps the in-service proof test at 125% of rated capacity unless the manufacturer recommends otherwise; eme completes the 125% test during production so the pre-service proof test is already done on delivery.
R
Rated Capacity
The maximum total hook load a crane or lifting device is certified to handle, including the load and all rigging hardware between the hook and the load. Rated capacity is marked permanently on the equipment per ASME B30.17 and is the authoritative working limit. Sometimes called “rated load” or “working load limit” (WLL) — though WLL more precisely refers to the sling or component rating in isolation.
Rigger
A specialist who plans, rigs, and executes lifts — particularly heavy, complex, or specialized lifts involving industrial machinery, plant relocations, or equipment installations. Riggers select the equipment, design the rigging configuration, verify load distribution and stability, and supervise or perform the lift. The rigging industry’s trade association is the Specialized Carriers & Rigging Association (SC&RA). Portable aluminum gantries are bought across multiple buyer segments — maintenance managers, project managers, facility engineers, rigging specialists — with riggers typically concentrated at the higher-capacity end (11,000 lb and 22,000 lb) because their specialized lifts trend heavier.
Rigging
The hardware and configuration used to attach a load to a crane’s hook — slings, chains, shackles, spreader beams, lifting beams, hooks, and related hardware. Also the process of selecting and arranging this hardware. Rigging hardware weight counts against the crane’s rated capacity and must be included in sizing calculations.
Roll While Loaded
The capability of a gantry crane to be rolled (repositioned on casters) while carrying its rated load, on a level prepared surface, within the manufacturer’s operational limits. Not all gantry cranes are rated for this service — most steel gantries and many cheap portable gantries are static-only. eme aluminum gantries are all designed and rated for roll-while-loaded service on level prepared surfaces. Full reference: Can a Gantry Crane Be Rolled While Loaded? →
S
Service Class
A classification under ASME BTH-1 indicating the expected fatigue life of a below-the-hook lifting device, expressed as a number of load cycles. Service Class 0 covers fewer than 20,000 cycles; Class 1 covers 20,000–100,000; Class 2 covers 100,000–500,000; Class 3 covers 500,000–2,000,000; Class 4 covers over 2,000,000. The service class determines fatigue analysis and inspection intervals.
Spreader Beam
A below-the-hook lifting device used to lift a load at two or more pick points simultaneously, with slings or chains extending from the ends of the beam down to the load. Distinct from a lifting beam (which picks up the load directly at points along the beam’s length). A spreader beam carries its load primarily as compression along the beam’s axis; a lifting beam carries its load as bending. Both are BTH-1 devices.
T
Trolley
The wheeled assembly that travels along a gantry crane’s main beam, carrying the hoist. The trolley allows horizontal positioning of the load along the length of the beam. Trolleys can be manually pushed, geared (hand-crank), or electric. On the eme gantry line, top beams and trolleys interchange across product ranges — a modular design that simplifies training and spare-parts inventory for fleets.
W
Working Load Limit (WLL)
The maximum load that a sling, chain, hook, or other rigging component is rated to handle, as specified by the component manufacturer. WLL includes the component’s design factor. In common usage, WLL and “rated capacity” are sometimes used interchangeably, though WLL is more specifically applied to individual rigging components while rated capacity refers to the assembled lifting device or crane.
Glossary entries last reviewed April 2026. Content reviewed by eme engineering for technical accuracy. Terms are added and refined on an ongoing basis; suggestions welcome at 1-888-679-5283.