Understanding Uniformly Distributed Load in Counterweight Theatre Rigging (Comprehensive)
A Comprehensive Technical Reference for Theatre Safety Professionals
This article is a slightly expanded version of our article here: https://entertainingsafety.com/knowledge-base/counterweight-rigging-udl/
Introduction
The safe operation of theatrical rigging systems depends fundamentally upon understanding how loads are distributed across structural elements. Among the most critical concepts for riggers, technical directors, and facility managers is the uniformly distributed load (UDL), a loading condition that occurs when weight is spread evenly along the length of a supporting member rather than concentrated at discrete points. This distinction has profound implications for structural behavior, counterweight balancing, and the prevention of catastrophic equipment failure.
In many theatres, battens are commonly fabricated from nominal 1½-inch Schedule 40 steel pipe (approximately 1.9 inches outside diameter and 0.145 inches wall thickness), though ANSI E1.4-1 specifies performance criteria for batten capacity and deflection rather than prescribing a specific pipe size (American National Standards Institute [ANSI], 2022). These battens span distances of 30 to 60 feet in most theatrical venues, supported at intervals by lift lines connected to sheaves, with the entire assembly balanced against counterweights on an arbor. When loads are applied to these battens in a uniformly distributed manner, the structural response differs markedly from point-loaded conditions, affecting bending moments, shear forces, deflection characteristics, and the forces transmitted to supporting hardware.
ANSI E1.4-1, Entertainment Technology: Manual Counterweight Rigging Systems, is the primary industry consensus standard for the design and performance of manual counterweight linesets. The standard requires that a typical batten be capable of supporting at least 30 pounds per linear foot of uniformly distributed load and a 100-pound point load at mid-span between adjacent lift lines, with deflection limited to approximately span divided by 180 (ANSI, 2022). These dual requirements recognize that actual loading conditions vary between productions, and battens must accommodate both distributed and concentrated forces.
For powered hoist systems, ANSI E1.6-1, Entertainment Technology: Powered Hoist Systems, addresses design, characteristic loads, testing, and labeling requirements. The standard requires hoist structures and load-carrying devices to be designed for characteristic loads, with limits on deflection and structural adequacy verified through calculation and testing. System signage must indicate both point-load and uniformly distributed load working load limits for each hoist (ANSI, 2019). The New York City Building Code further specifies that scenery battens shall be designed for a minimum load of 30 pounds per linear foot, with an impact factor of 75% applied to batten design calculations (New York City Department of Buildings, 2022).
This article provides theatre safety professionals with the technical foundation necessary to evaluate uniformly distributed loading conditions on counterweight rigging systems. The content addresses fundamental structural engineering principles, governing industry standards, practical calculation methodologies, and operational considerations that affect the safe management of UDL in theatrical environments. Throughout, emphasis is placed on the real-world application of these concepts within the constraints of professional and educational theatre operations.
Fundamental Principles of Uniformly Distributed Loading
Definition and Characteristics
A uniformly distributed load represents a loading condition where force is applied consistently along the length of a structural member, measured in units of force per unit length, typically pounds per linear foot (plf) or Newtons per meter (N/m). Unlike point loads, which concentrate force at a single location, UDLs spread their effect across the entire span, creating a fundamentally different stress distribution within the loaded member.
The mathematical representation of a UDL expresses the load intensity as w, where the total load W equals the product of load intensity and span length: W = w × L. This relationship allows conversion between total load calculations and distributed load analysis, essential for comparing different loading scenarios on theatrical battens. For a batten spanning 40 feet with a UDL of 10 plf, the total load equals 400 pounds, distributed such that each linear foot of the batten carries precisely 10 pounds of weight.
True uniform distribution requires that weight be spread perfectly evenly, a condition that theatrical applications frequently approximate but rarely achieve exactly. When lighting instruments of identical weight are spaced at regular intervals along a batten, the resulting load approaches uniform distribution, though technically it consists of multiple point loads. Industry practice treats closely spaced, equally weighted elements as a UDL when the spacing is small relative to the span length, generally accepting this approximation when fixture spacing falls below two feet.
Comparison with Point Loading
Understanding the behavioral differences between uniformly distributed and point loads is essential for theatrical rigging applications. When a point load P is applied at the midspan of a simply supported beam, the maximum bending moment occurs at the load location and equals M = PL/4. For the same total load applied as a UDL, the maximum bending moment at midspan equals M = wL²/8, which can be rewritten as M = WL/8 where W represents total load. Comparing these expressions reveals that a point load at midspan creates a bending moment twice as severe as the same total load distributed uniformly.
This distinction has direct implications for batten capacity ratings. When manufacturers or engineers establish working load limits for theatrical battens, they must specify whether the rating applies to UDL or point load conditions. ANSI E1.4-1 addresses this by requiring systems to handle both 30 plf distributed and 100-pound point loads, recognizing that actual loading conditions vary between productions (ANSI, 2022). The requirement for both capacities ensures that battens can safely accommodate the range of loading scenarios encountered in theatrical use.
Deflection behavior also differs substantially between loading types. For a simply supported beam under UDL, maximum deflection at midspan equals δ = 5wL⁴/(384EI), where E represents the modulus of elasticity and I the moment of inertia. Under an equivalent midspan point load, maximum deflection equals δ = PL³/(48EI). The UDL case produces approximately 60% of the deflection created by an equivalent point load, assuming equal total weight. This relationship explains why a batten that appears acceptable under distributed scenery might deflect unacceptably when a heavy point load is added at center.
Bending Moment and Shear Force Relationships
The internal forces developed within a beam under UDL follow predictable mathematical relationships derived from static equilibrium and mechanics of materials principles. For a simply supported beam of length L carrying a UDL of intensity w, the reactions at each support equal wL/2, representing half the total distributed load. The shear force varies linearly from positive wL/2 at the left support, passing through zero at midspan, to negative wL/2 at the right support.
The bending moment diagram for UDL on a simply supported beam follows a parabolic curve, reaching maximum value at midspan. This maximum moment, given by M = wL²/8, represents the critical design condition for sizing structural members. The section modulus S of the beam must be sufficient that the bending stress σ = M/S remains below allowable limits established by applicable codes. For Schedule 40 steel pipe commonly used as theatrical battens, AISC 360-16 provides the basis for determining allowable bending stresses (American Institute of Steel Construction [AISC], 2016).
Shear force, while generally less critical than bending for typical batten applications, becomes significant at connection points and requires consideration in splice design. The maximum shear at supports equals the reaction force wL/2, diminishing linearly toward midspan. Batten splice locations should be positioned away from maximum shear regions, and fastener capacity must account for shear transfer requirements. Industry practice places splices at roughly quarter-span locations where shear forces are reduced, though specific positioning depends on lift line spacing and load patterns.
Continuous Beam Analysis for Multi-Span Battens
Theatrical battens rarely function as simple beams supported at only two points. Instead, they behave as continuous beams spanning multiple supports created by lift lines at regular intervals. This continuous beam behavior fundamentally alters the distribution of bending moments and shear forces compared to simply supported conditions, generally resulting in reduced maximum moments and deflections.
Two-Span Continuous Beam Behavior
When a batten spans across three lift line points creating two equal spans, each of length L, the structural behavior becomes statically indeterminate. Analysis using the three-moment equation or moment distribution reveals that reactions at exterior supports equal 3wL/8, while the interior support carries 10wL/8, representing 1.25 times the load per span. The maximum positive bending moment in each span equals 9wL²/128, occurring at approximately 0.375L from the exterior support, while negative moment over the interior support reaches wL²/8.
Maximum deflection for two-span continuous beams under UDL equals approximately 0.00541wL⁴/(EI), occurring at roughly 0.42L from each exterior support. This deflection magnitude represents approximately 40% of that for a simple beam spanning the same distance, demonstrating the structural efficiency gained through continuity. This reduced deflection allows longer spans between lift lines or greater load capacity for a given batten size.
Three-Span and Multi-Span Configurations
For three equal spans under UDL, moment coefficients become more complex. Interior reactions exceed exterior reactions, and the moment pattern includes both positive moments within spans and negative moments over interior supports. The maximum positive moment occurs in the end spans at coefficient of 0.08wL², while interior span positive moment reaches 0.025wL². Negative moments over interior supports equal approximately 0.10wL² for supports adjacent to end spans and 0.10wL² at the center support.
Published batten capacity data from rigging manufacturers typically bases calculations on continuous beam assumptions with three or more spans, recognizing that most theatrical installations include multiple lift lines. JR Clancy’s published batten load tables explicitly state that calculations assume battens continuous over three spans with extension beyond the last lift line of three feet or less (Wenger Corporation, 2024). These assumptions allow manufacturers to provide higher working load limits than would be appropriate for simple beam conditions.
When battens extend beyond exterior lift lines as cantilevers, the overhang length affects moment distribution throughout the system. Standard practice limits overhang to approximately three feet, beyond which the beneficial moment redistribution diminishes and cantilevered sections may experience excessive deflection. Longer overhangs require specific engineering analysis rather than reliance on standard tables.
Deflection Criteria and Serviceability Requirements
Deflection limits serve both functional and safety purposes in theatrical rigging applications. Excessive batten sag creates visible curvature that affects scenic appearance, causes lighting instruments to aim incorrectly, and allows scenic elements to shift position during movement. Beyond aesthetics, severe deflection indicates stress levels approaching structural limits and may signal inadequate load capacity.
Industry Standard Deflection Limits
ANSI E1.4-1 establishes that a typical batten shall limit deflection to approximately L/180 of the span between suspension points under specified loading conditions (ANSI, 2022). This limit applies to manual counterweight systems and has been widely adopted as a baseline criterion. The L/180 criterion balances practical construction realities with acceptable performance for theatrical applications.
For a typical ten-foot span between lift lines, the L/180 limit allows maximum deflection of 0.67 inches under design load. This relatively generous allowance recognizes the practical realities of theatrical operation, where some visible deflection is acceptable provided it does not impair function or safety. More stringent limits of L/240 or L/360, common in architectural applications where occupant comfort is paramount, would significantly reduce allowable batten loads but may be appropriate for lighting positions where instrument aim accuracy matters.
For powered hoist systems, ANSI E1.6-1 requires that system design address deflection as part of the overall structural adequacy verification. The standard defines characteristic load as the maximum load imposed during normal operation, including working load limit, weight of load-carrying devices, and inertial forces due to acceleration (ANSI, 2019). Deflection under characteristic load must be controlled through appropriate structural design, though the specific limit depends on the engineered system design rather than a universal prescriptive value.
Calculating Maximum Deflection
For a simply supported beam under UDL, maximum deflection at midspan is calculated using the formula δ = 5wL⁴/(384EI). This expression requires consistent units: load intensity w in pounds per inch, span L in inches, modulus of elasticity E in psi (29,000,000 for steel), and moment of inertia I in inches to the fourth power. For NPS 1½” Schedule 40 steel pipe, the moment of inertia equals approximately 0.31 in⁴.
Applying this formula to a 120-inch span (10 feet) with 0.833 lb/in distributed load (10 plf) yields: δ = 5 × 0.833 × 120⁴/(384 × 29,000,000 × 0.31) = 0.24 inches. Comparing this to the L/180 deflection limit of 0.67 inches confirms that the batten operates well within allowable deflection. However, increasing the span to 15 feet (180 inches) while maintaining the same load produces deflection of approximately 1.2 inches, exceeding the L/180 limit of 1.0 inch and indicating the need for either reduced loading or additional support points.
Continuous beam conditions reduce deflection significantly. For a batten continuous over three equal spans under UDL, maximum deflection in the end spans approximates 0.00541wL⁴/(EI), roughly 40% of the simple span case. This structural efficiency explains why multi-point suspension systems achieve greater capacity than would be possible with simple two-point support.
Dynamic Loading Considerations
Static analysis of UDL conditions, while fundamental, does not fully capture the forces experienced by theatrical rigging systems during operation. When battens move, whether raised, lowered, or stopped, dynamic forces develop that temporarily increase the effective load on structural components. Understanding these forces is essential for safe rigging practice.
Acceleration and Deceleration Effects
Newton’s second law dictates that accelerating a mass requires force beyond that needed to support it statically. When a 600-pound batten assembly accelerates upward at 0.1g (approximately 3.2 ft/s²), the effective load increases to 660 pounds. This 10% increase, though seemingly modest, accumulates across multiple system components and must be accommodated by appropriate capacity margins.
ANSI E1.6-1 addresses dynamic effects through the characteristic load concept, defined as the maximum load that can be imposed by the hoist during normal operation, including working load limit, weight of load-carrying devices, and inertial forces due to acceleration (ANSI, 2019). The standard provides methodology for determining characteristic load based on system parameters, enabling designers to account for operational dynamics without requiring detailed force analysis for each movement.
Deceleration creates greater concern than acceleration in most rigging applications. Stopping a moving load requires deceleration force that adds to gravitational load. Abrupt stops, whether intentional or resulting from equipment malfunction, can generate forces substantially exceeding normal operating conditions. The New York City Building Code applies a 75% impact factor to batten design, effectively requiring battens sized for 175% of nominal load to account for dynamic effects (New York City Department of Buildings, 2022).
Shock Loading and Impact Events
Shock loads represent extreme dynamic events where force application occurs over very short time intervals. Unlike gradual acceleration, shock loading can multiply effective load by factors of two, three, or more depending on the severity of the impact event. Common sources of shock load in theatrical rigging include runaway line sets striking limit stops, sudden counterweight release, and emergency stops of powered systems.
The physics of shock loading relates deceleration distance to force multiplication. When a 500-pound load moving at 2 ft/s stops within 0.1 feet, the deceleration equals 20 ft/s², creating an impact force of approximately 810 pounds, a 62% increase over static weight. Reducing the stopping distance to 0.05 feet doubles the deceleration and increases impact force to approximately 1,120 pounds. These calculations illustrate why smooth, controlled movements with adequate stopping distances are essential for managing dynamic forces.
Design factors incorporated into rigging equipment ratings provide margin against shock events, but these margins are intended for occasional, unavoidable impacts rather than repeated abuse. A component rated at 1,000-pound working load limit with 5:1 design factor can theoretically withstand 5,000 pounds before failure. However, this capacity exists to survive rare emergency conditions, not to accommodate routine shock loading that would rapidly accumulate fatigue damage. Training personnel to operate systems smoothly and maintain proper counterweight balance remains the primary defense against dangerous dynamic forces.
Applications of UDL in Theatrical Rigging
Soft Goods and Drapery
Theatrical soft goods, including main drapes, legs, borders, backdrops, and cycloramas, represent the most common source of uniformly distributed loads on counterweight systems. When properly attached using continuous webbing, ties distributed along the batten length, or similar methods, drapery weight spreads evenly rather than concentrating at attachment points. A 40-foot grand drape weighing 400 pounds creates a UDL of 10 plf when suspended from a full-width batten.
Fabric weight varies significantly with material selection. Cotton velour at 25 oz/yd² weighs approximately 0.5 pounds per square foot, while heavy wool serge may exceed 1.0 pound per square foot. A typical 20-foot tall grand drape with 50% fullness (30 running feet of fabric for 20 feet of opening) in 25 oz velour weighs approximately 300 pounds, creating 7.5 plf on a 40-foot batten. Replacing this with heavy wool could double the load to 15 plf.
Cycloramas and scrims present unique loading considerations due to their typically lighter weight but greater width. A muslin cyclorama 60 feet wide by 30 feet tall may weigh only 150 pounds, creating merely 2.5 plf. However, the extreme width requires longer battens and more lift lines, with correspondingly increased attention to deflection control. Even slight sag across 60 feet creates visible undulation that detracts from the seamless appearance these elements are intended to provide.
Lighting Positions
Electric battens supporting lighting instruments approximate UDL conditions when fixtures are spaced regularly at consistent weights. Modern LED fixtures typically weigh 15 to 30 pounds each, while conventional ellipsoidals may weigh 25 to 45 pounds depending on manufacturer and lamp type. A 50-foot electric with 25 fixtures at 30 pounds each (750 total pounds) hung at 2-foot spacing creates an effective UDL of 15 plf.
Cable weight adds significantly to lighting position loads and must be included in capacity calculations. Multi-conductor feeder cable commonly used in theatrical applications weighs 0.5 to 1.5 pounds per foot depending on conductor count and gauge. A 50-foot run of 12/14 cable adds approximately 25 to 75 pounds to the electric, increasing effective UDL by 0.5 to 1.5 plf. Venues with extensive cable runs should account for this additional distributed load when planning lighting positions.
The approximation of point loads as UDL becomes less accurate as fixture spacing increases or weights vary significantly. When heavy moving lights are interspersed with lighter conventional fixtures, point load analysis at each fixture location may be more appropriate than averaged UDL treatment. Hybrid approaches that model heavy fixtures as point loads superimposed on a distributed base load from lighter instruments often provide the most accurate capacity assessment.
Scenic Elements
Flown scenery creates the most variable loading conditions encountered in counterweight rigging. Unlike soft goods and electrics with relatively predictable weights, scenic elements range from lightweight fabric panels to heavy built structures. When scenic pieces contact the batten along their full length, as with drops sewn to webbing or flats attached by continuous french cleats, UDL assumptions apply reasonably well.
Hard-framed scenery often creates point loading rather than distributed conditions. A 20-foot wide flat hung from three attachment points places concentrated loads at each pickup location, requiring point load analysis for accurate assessment. Even when multiple pickups are used, the discrete nature of the connections differs fundamentally from the continuous contact of properly installed soft goods.
Scenic automation introduces additional complexity by potentially varying both load magnitude and distribution during performance. A tracked wagon that parks beneath a flown piece, then receives load transferred from the fly system, creates conditions where the batten load changes substantially during the show. Careful documentation of loading conditions throughout the production run, combined with appropriate verification of counterweight settings, becomes essential for safe operation.
Comprehensive Calculation Example
The following example demonstrates complete analysis of a uniformly distributed load on a theatrical batten, integrating concepts presented throughout this article. This scenario represents typical conditions encountered in educational and community theatre venues where detailed engineering analysis may not be readily available.
Problem Statement
A manual counterweight system includes a 36-foot batten constructed from NPS 1½” Schedule 40 steel pipe. The batten is supported by four lift lines spaced at 10-foot intervals, with the exterior lift lines located 3 feet from each end of the batten. The production requires hanging a cyclorama weighing 180 pounds uniformly distributed across the full batten length. Determine whether this loading condition is acceptable based on deflection criteria and compare actual conditions to ANSI E1.4-1 requirements.
Given Information
Batten length: 36 feet (432 inches). Pipe specification: NPS 1½” Schedule 40, OD = 1.900″, wall = 0.145″. Moment of inertia (I): 0.310 in⁴. Modulus of elasticity (E): 29,000,000 psi. Lift line locations: 3 ft, 13 ft, 23 ft, 33 ft from one end. Span between lift lines: 10 feet (120 inches). Cyclorama weight: 180 pounds total. Load intensity: 180 lbs / 36 ft = 5.0 plf = 0.417 lb/in.
Analysis
The batten functions as a continuous beam over three interior spans with 3-foot cantilevers at each end. For the interior spans under UDL, using continuous beam coefficients for three equal spans, maximum positive moment in end spans occurs at approximately 0.4L from exterior supports and equals roughly 0.08wL². Maximum negative moment over interior supports equals approximately 0.10wL².
For this loading: w = 0.417 lb/in, L = 120 in. Maximum positive moment: M = 0.08 × 0.417 × 120² = 481 lb-in. Maximum negative moment: M = 0.10 × 0.417 × 120² = 601 lb-in.
Maximum deflection in end spans for continuous beam under UDL approximates δ = 0.0054wL⁴/(EI) = 0.0054 × 0.417 × 120⁴/(29,000,000 × 0.31) = 0.052 inches.
Comparing to L/180 deflection limit: L/180 = 120/180 = 0.67 inches. Actual deflection of 0.052 inches is approximately 8% of allowable, indicating substantial reserve capacity.
Verification Against Standards
ANSI E1.4-1 requires that a typical batten support both 30 plf of uniformly distributed load and a 100-pound point load at mid-span between adjacent lift lines, while limiting deflection to approximately L/180 (ANSI, 2022). The cyclorama creates only 5.0 plf, representing 17% of the minimum required distributed load capacity. This confirms the batten has substantial reserve for additional loading from lighting instruments, additional scenic elements, or production changes.
Counterweight requirement: Total load of 180 pounds plus batten weight (approximately 80 pounds for 36 feet of Schedule 40 pipe at 2.27 lb/ft) equals 260 pounds. The arbor requires counterweight matching this load, with adjustment for arbor and operating line weight per standard counterweight balancing procedures.
Safety Considerations and Inspection Requirements
Load Verification Procedures
Accurate load determination forms the foundation of safe rigging practice. Weighing scenic and soft goods elements before loading provides essential data that estimates alone cannot reliably provide. Fabric weights vary with material, weave, and finish treatments, while scenic construction weights depend on lumber species, fastener quantity, and applied finishes. Scale measurements eliminate guesswork and enable precise counterweight balancing.
For elements too large for available scales, sectional weighing of representative portions allows reasonable estimation. Weighing a measured length of drapery fabric establishes weight per linear foot, which can be multiplied by total fullness. Similarly, weighing a standard four-by-eight sheet of the plywood used in scenic construction allows calculation of total flat weights based on area.
Ongoing load tracking through production changes prevents dangerous accumulation of unrecorded additions. Establishing systems for documenting every item added to or removed from battens, maintained consistently throughout the production run, ensures that counterweight settings remain accurate as productions evolve. This discipline becomes particularly important in repertory situations where multiple productions share fly system resources.
Visible Deflection as Warning Sign
Observable batten deflection provides immediate visual indication of loading conditions. When deflection becomes clearly visible from working level, loads have typically reached or exceeded design limits intended for normal operation. Training all personnel who work around rigging systems to recognize and report visible deflection creates an additional layer of safety monitoring beyond formal inspection programs.
Deflection should be evaluated with battens at trim height under full production load. Slight deflection that appears acceptable with battens high in the fly space may become unacceptable when trim brings the load closer to eye level. Additionally, deflection that develops gradually over time may indicate material fatigue or fastener loosening requiring investigation regardless of load changes.
Regular Inspection Programs
ANSI E1.4-1 requires pre-operational checks before each use and periodic detailed inspections at intervals appropriate for the intensity of use (ANSI, 2022). Pre-operational checks verify that visible components appear in good condition and counterweight balancing is appropriate for intended loading. Detailed inspections by qualified persons examine all system components for wear, damage, and proper adjustment.
Batten splices require particular attention during inspection. Internal sleeves should be examined for proper fastening, with bolts or roll pins checked for tightness and condition. Any relative movement between joined pipe sections indicates splice failure requiring immediate correction. Similarly, trim clamp attachment points should be inspected for damage to pipe surfaces that might indicate overloading or improper installation.
Documentation of inspection findings, corrective actions, and maintenance activities creates the institutional record necessary for demonstrating due diligence and tracking system condition over time. ANSI E1.6-1 provides specific record-keeping requirements for powered systems that represent good practice for manual systems as well (ANSI, 2019).
Conclusion
Understanding uniformly distributed loads in theatrical rigging systems requires integration of structural engineering principles with practical operational knowledge. The mathematical relationships governing beam behavior under UDL conditions, while grounded in mechanics of materials theory, find direct application in evaluating batten capacity, verifying deflection compliance, and managing counterweight balance throughout productions.
Key principles for practitioners include recognition that UDL creates lower peak stresses than equivalent point loads, that continuous beam behavior significantly reduces deflection compared to simple spans, and that dynamic effects during system operation temporarily increase effective loads beyond static values. These concepts inform decisions about load placement, support spacing, and operational procedures that collectively determine system safety.
ANSI E1.4-1 and ANSI E1.6-1 establish performance requirements that define acceptable system capacity for manual and powered rigging systems respectively. Meeting these standards requires appropriate equipment selection, proper installation, ongoing maintenance, and operational practices that respect system limits. When questions arise about specific loading conditions or system capacity, consultation with qualified engineering professionals provides the authoritative analysis necessary for sound decision-making.
The ultimate goal of understanding UDL in counterweight rigging extends beyond technical compliance to the fundamental objective of protecting all persons who work on, around, or beneath theatrical rigging systems. Technical knowledge applied with consistent discipline creates the foundation for safe theatrical production.
References
American Institute of Steel Construction. (2016). Specification for structural steel buildings (ANSI/AISC 360-16). AISC.
American National Standards Institute. (2019). Entertainment technology: Powered hoist systems (ANSI E1.6-1). ESTA.
American National Standards Institute. (2022). Entertainment technology: Manual counterweight rigging systems (ANSI E1.4-1). ESTA.
Gere, J. M., & Goodno, B. J. (2018). Mechanics of materials (9th ed.). Cengage Learning.
New York City Department of Buildings. (2022). New York City building code 2022. NYC Department of Buildings.
Wenger Corporation. (2024). Allowable batten loads. JR Clancy. https://www.wengercorp.com/irigging/battens.php