Thursday, April 29, 2010

Fly me to the moon (safely)

It comes-up all too frequently:  Someone wants to present Jesus rising to Heaven, Mary Poppins, Peter Pan, Circus de Soleil, Witches, Monkeys, or someone being levitated into a spaceship (followed by the snap of a rubber glove the aliens are putting-on . . .), and the question comes-up:  "How are we going to fly them?"  The question should be:  "How are we going to fly them SAFELY?"  Well, start here:

The North American Association of Flying Effects Directors (NAAFED) 2010 Performer Rigging Workshop will be held Wednesday, May 19 through Saturday, May 22, at Northern Illinois University in DeKalb, IL. The cost to attend the workshop is $600, and there is a $50 discount for ETCP certified riggers, USITT, CITT, EdTA, or IATSE members. Verification will be required. Students can use both discounts.

The workshop is designed for all ages and skill levels. Practical application will follow lecture-based presentations to provide attendees with the opportunity to practice the theory they learn. By the end of the workshop, they will have progressed from learning the basics of rigging, physics, and mechanical advantage to flying each other safely. Taught by ETCP Recognized Trainers, all attendees will receive 1 ETCP renewal credit per hour.

Online registration is available at

Fly safe, otherwise you may never get to use those frequent flier miles you've been saving.

Friday, April 23, 2010

STOP! In the name of love (of keeping your body parts intact)

I don't know about you, but when it comes to power tools, they can be a bit scary when you realize that they can grab your cloths, hair, or the part you are working on and tear them-up in a fraction of a second.  Drill presses, router tables, planners, and table saws are some of the most powerful tools in your shop, so having a shut-off switch that is extremely visible and easy to slam a hand or knee onto is a really good idea.

Grizzly Power Tools ( makes the H8243 mondo power switch for this application.  For the price of a good pizza this dual voltage, single-phase Paddle Switch is rated for 110 Volt, 2 HP motors up to 35 amps, and 220 Volt, 3 HP motors up to 20 amps. The large paddle makes this switch ideal for emergency shut-offs.  It fits a standard single-gang electrical box, so you can mount it just about anywhere.

ANSI Standard 535.1 requires that the RED switch be mounted on a yellow background for maximum visibility, so slap a coat of yellow down before you mount that switch.

Do I have to have this?

According to most international machinery safety standards you probably should.  Here is a listing of relevant requirements for E-stops:
  • 98/37/EC The Machinery Directive - Clause 1.2.4 in annex 4 gives requirements for the emergency stop function for new machines. See also clause 1.2.2 Control devices (chapter “Standard and Regulations”).

    Council Directive 89/655/EEC of November 30, 1989 concerning the minimum safety and health requirements for the use of work equipment by workers at work, Clause 2.4 gives the requirements for the emergency stop function for older machines. See also clause 2.1 (chapter “Standard and Regulations”).
  • EN ISO 13850 Safety of Machinery - Emergency stop—Principles for design.  A harmonized standard that gives technical specifications for the requirements on the Machinery Directive.  Can also be used for older machinery.
  • EN 60204-1 Safety of Machinery - Electrical equipment of machines —Part 1: General requirements.  This is a harmonized standard that gives requirements for the electrical equipment of machinery including the emergency stop actuator/function. See clauses 9.2.2 and
  • OSHA publication "Safeguarding Equipment and Protecting Employees from Amputation" can be downloaded here:

For industrial safety switch systems that meet a much higher level of performance, you need to look toward systems that are engineered solutions that utilize specialized sensors, switches, relays, and annunciators.  While the Grizzly paddle switch is a huge step in the right direction, there is still much more you can do to safeguard your shop workers.

Also see: 

Thursday, April 22, 2010

Oh! My Aching Back!

It is estimated that 80% of the population has experienced back pain or discomfort in their working lives.  In the theatre we move a lot of equipment around, many times while reaching out or leaning over railings.  Stacking boxes, loading trucks, lifting counterweights, moving chairs, and working with platforms and staging are but a few of the things we do that could strain your back.

When we lift a load, we use muscles in the low back as part of a lever system. Unfortunately, because the muscles in our low back are only about two inches from the spine, the further a load is from our body, the more stress transfers to the low back and the amount of work required increases. Think about snow on the branch of a tree; the further the snow is from the trunk, the more the branch bends under its weight.

The National Institute for Occupational Safety and Health (NIOSH) developed a model that determines whether a lifting task is safe. The result of the NIOSH Lifting Equation is the Recommended Weight Limit (RWL), a weight that 99% of males and 75% of females should be able to lift safely. Under perfect circumstances lifting an object with good handles only once in a certain posturethe highest possible RWL is 51 pounds. In calculating the RWL, other factors are also considered including horizontal distance, vertical location at the beginning of the lift (floor level is the least desirable), and whether there is twisting during the lift.

The NIOSH Lifting Equation makes it is easy to identify opportunities for design improvements. By working with the numbers, you can quantify the risk reduction that results from raising a load from the floor (0") to table height (30"), or decreasing the width of a table to minimize reach distance. The equation is equally useful for identifying ergonomic solutions, as well as ergonomic challenges.

Use the right tool for the job!
When I was about 10 years old I was sitting at the kitchen table trying (without much success) to strip the insulation from a 26 gauge wire with a big old and well worn set of linesman’s Kleins (heavy duty wire cutters for 8 & 10 gauge solid conductor steel wire).  My father came by and saw my frustration, brought me a set of small gauge wire strippers, and lectured me: ”Don’t use a Blacksmith’s tools to do a Jeweler’s job!”  We have forklifts, pallet jacks, carts, winches, pulleys, block-and-tackle, j-bars, and most importantly — other people, to help us. We are not Iron Man, Superman, or the Incredible Hulk, so don’t be shy, get help!  It’s better to be called a ‘wimp’ than to be called at the hospital.

Caveat to the Equations:  The NIOSH Lifting Equation does not apply if any of the following occur:
  • Lifting/lowering with one hand
  • Lifting/lowering for over 8 hours
  • Lifting/lowering while seated or kneeling
  • Lifting/lowering in a restricted workspace
  • Lifting/lowering unstable objects
  • Lifting/lowering while carrying, pushing or pulling
  • Lifting/lowering with wheelbarrows or shovels
  • Lifting/lowering with high-speed motion (faster than 30 inches/second)
  • Lifting/lowering with unreasonable foot floor coupling (<0.4 coefficient of friction between the sole and the floor)
  • Lifting/lowering in an unfavorable environment (i.e., temperature significantly outside of 66-79 degree F range; relative humidity outside 35-50% range
So, that covers almost everyting we do in the theatre.  What good are all these equations?  What can we do?  Think before your lift!  When in doubt, get help.  Ergonomics aren't about egos or machismos - it's about planning your work task so it doesn't tear-up your body.  Work smarter, not harder.

NIOSH Lifting Equation (on-line calculator):
UCLA Ergonomics Lab:
Canadian OSH (with online metric calculator):

Wednesday, April 21, 2010

How fast can you figure-out your Fall Protection Clearance?

PeakWorks has released a new application for the iPhone that calculates the clearance required for your fall arrest system to function properly.

They seemed to resist the urge to call it iFall.  The free application calculates the safe distance required based upon the harness type, anchor point elevation, and other factors.  More information about the application can be found at:

Information about PeakWorks fall protection systems can be found at:

Tuesday, April 20, 2010

Rung for your life!

Ever have to make one of those reeeally long ladder climbs?  Didja wonder if you were ever going to get to the top (or the bottom, for that matter)?  Your hands can get sweaty and your boots might have a bit 'o crud on them . . . you get a bit tired . . . next thing you know:  you lose your grip, or your foot misses the mark.  This may be an annoyance, or it could be a lot worse.

Fall protection systems for ladders are only required for ladders more than 15 feet tall (you can see the harness attachment rail at the center line of this one).  This may keep you from falling to the ground, but you may still bust your face on the ladder before you regain you composure (yet another good reason to have a chin strap on your hard-hat!).

Many of the ladders you may encounter are right at or just short of the 15 foot limit, so all you have to protect you is your good grip on the ladder.  You can install fall arrest devices on ladders less than 15', too, and it is a really good practice.

Safeguard Technologies has a solution:  Formed fiberglass overlays that are fabricated to fit a variety of ladder rung diameters from 3/4" to 2" diameter.  The covers have hi-traction grit embedded in the material to provide a slip-resistant texture to the surface.  These can be applied to scaffold climbing rails, too, which are notoriously slippery - why do the scaffolding manufacturers coat these with glossy powder-coat paint?!
A ladder rung cover being installed with adhesive.

Ladders rungs nicely visible and with very high traction.

Now for the cool part:  Since these are made-to-order to fit the rung width and rung diameter of your facility's ladders, they can fabricate the rung covers with photoluminescent pigment in the fiberglass binder.  This can help you find your way down from the catwalk or gridiron in the dark should the power go out.

Resource:  Safeguard Technology (

Friday, April 16, 2010

So, just where is that Fire Extinguisher? I know I saw around here somewhere . . .

Oh, here it is - tucked away behind this fake ficus tree.  It's a good thing we have decorative things to cover-up those ugly fire fighting tools!  It sure would be terrible if the audience actually saw them.
Ref: OSHA: 1910.157 Fire Protection - Portable fire extinguishers.

"1910.157(c)(1) The employer shall provide portable fire extinguishers and shall mount, locate and identify them so that they are readily accessible to employees without subjecting the employees to possible injury."

Thursday, April 15, 2010

Yup, we've got all of our Fire Extinguishers safely locked away . . .

  1. Find Key to Fire Extinguiser cabinet padlock, go to step 5, -or-
  2. Find safety goggles and put them on.
  3. Find heavy object to bash out glass.
  4. Reach past broken glass edges and retreieve Fire Extinguisher.
  5. Find wire cutter.
  6. Cut tie wire on Safety Pin.
  7. Pull Pin.
  8. Aim at base of fire.
  9. Squeeze handle.
  10. Sweep back and forth across base of fire.
Do ya think maybe some one missed the training module about putting-out little fires BEFORE they become BIG FIRES?

Wednesday, April 14, 2010

The Big Red Word vs. the Little Green Man

SLATE author Julia Turner has a great article about the ongoing controversy between the common US  EXIT  sign and the internationally recognized ISO standard 'running man' sign.

You can read it here:

Friday, April 9, 2010

Get a grip - a really tight grip

Tools for crimping compression ovals onto wire rope cable can be, shall we say, a bit unwieldy at times.  Actually, almost always.  An if you are not built like a linebacker, they can flat wear you out if you have dozens - nay hundreds - of crimps to perform.  Enter a really workable solution from Nicopress:  The
Nicopress® Model 5606.  Much cooler than Luke Skywalker's Light Saber (but only because you can actually own one of these).

• One hand operation; lightweight & slim
• Visible orange weather resistant housing
• Audible bypass when predetermined pressure is achieved
• Crimping jaws can be opened mid-cycle to adjust connection
• Crimp cycle time:  Less than 6 seconds
• Battery charge time: Less than 1 hour, about 250 sleeves for 1/4" wire rope can be compressed per charge.
• Jaws rotate 360 degrees for ease of use in confined spaces.
• Weight: 6.75 lbs. with Lithium Ion Battery
• Dimensions: 20.5" L x 4" H x 2.5" W
• Wire Rope Die Sizes: 3/64" thru 5/16" diameter

The top button (thumb) initiates the crimp action, and the bottom button releases the jaws.

Interesting side note:  The crimp dies for 1/4" wire rope only require two compressions, unlike the hand tool's three, so when you are doing inspections, and find fewer crimps, it doesn't necessarily mean that it was done wrong, but instead it may have been done with a different tool / die than what you are accustomed to seeing.

Info at:

Wednesday, April 7, 2010

You can Huff and Puff, but you won't blow down this Brickhouse

Say what you will about counterweight rigging being medieval, it still goes into a lot of stages and is used every day by many people.  So, if you're going to do it, you might as well make it safer.  At USITT 2010 in Kanasas City, Thern Stage Equipment Company introduced the "Brickhouse Front-Loading Counterweight Arbor System".  This takes a whole new approach at how you handle the counterwights as they are loaded and unloaded, and also takes a new look at securing them in the arbor carraige.

The first thing one notices it that the Brickhouse has side walls and three compartments for counterweights.  This allows you to load weights into the most convenient compartment to access, rather than reaching high or low and possibly overextending oneself.

The next convenience is that as you place weights in the Brickhouse, you don't need two hands to do it.  No awkward twisting, tilting, or finagling of the weights to get them in-between the arbor rods.  Why?  Well, there is no back rod, and the front rod conveniently swings out of the way so you can just slide the weight 'bricks' into the compartment, which is sloped a bit to help with the process.

The weights have a handle built right into them, too.  What a concept:  A counterweight that you can grab onto with one hand and hold it securely without fear of dropping it.  This leaves your other hand free to hang-on for dear life (you are wearing a fall prevention / arrest system as you load weights, right?)

Once the weights are nestled into their compartments (and you can fill the compartments all the way to the top, too), you just swing the front arbor rod back into place and let 'er fly.

Drop testing shows that a stage heavy line set will crash throught the lower arbor stop just like a regular arbor (no surprise there), however, the side walls are built to take a lickin'-and-keep-on-tickin', so you shouldn't have a mess of bricks jumping out of the Brickhouse.  No word yet on the potential for bricks jumping out of the Brickhouse in the event of a stage-heavy run-away, but given the design of the compartments, it looks like the weight-lock free design still keeps them under control and not raining-down a hail storm of steel plates on the fly crew should a line set get away from you.  That said, I'm still wearing my hard hat PPE when I'm onstage or in the fly galleries - there are still a lot of other hazards out there to ping your skull.

More info can be had at:

Sunday, April 4, 2010

Yech! Get that stinky thang out of my grille!

It's 10:00 o'clock.  Do you know where your microphone has been?  Who's been playing tonsil hockey with it?  Or worse?  Didn't think so.  Most people don't bother to think about those things.  Too yucky.  I know it puts shivers down my spine when I do.

Fortunately, somebody does care.  The folks at Microphome have just what you and your band needs to keep from contracting the next deadly thing (well, at least it might make those stupid germs think twice about who they're foolin' with).  Professional Mic Cleaning FoamDon't leave home without.  They claim it kills 99.9% of germs on the stuff it touches.

Check-out the product at -or- (which in this case I'm thinkin' they mean organism).

It's just like spraying shaving cream on your favorite '58, but it's hittin' the gross stuff head-on.

For another blog entry on the subject, see:

If you still don't  believe this is a good idea, then go to:

What's on your mic?

Saturday, April 3, 2010

Doors - Not just for Jim Morrison

Did you know that Fire Doors must be inspected annually? Yup, just like a Fire Curtain. Ref: 2010 NFPA 80, chapter 5.2.1. Most doors in an institutional building are Fire Doors, and an easy way to verify if a door is a Fire Door it is to look at the edge of the door leaf that is attached to the hinges.

If it is a Fire Door then you will see a small metal placard that says: FIRE DOOR and a bunch of other information about the door.  Look closely if you don't see it at first -- it may have been painted-over -- which is also a fire code violation. Ref: 2010 NFPA 80, chapter 4.2.2.

Inspections of Fire Doors are to check that the door is:
  • There (yes, I find them missing sometimes).
  • In proper operating condition (windows not broken, operating hardware all functioning).
  • The latches work (and aren't covered with gaffer's tape) - this is so the door can stay closed against the atmospheric forces of a fire.
  • The crash-bar (panic hardware) works and allows the door to open (no extra dead-bolts, pad-locks, or chains).
  • To make sure the door is not blocked on either side in a manner that would prevent it from being opened (things like pianos, stacks of chairs or desks, book cases, filing cabinets, cars, trucks, orchestra shells, etc.).
  • To make sure that the door is not propped open in a manner that would prevent it from being closed automatically (this means NO stage weights, NO chairs, NO desks, NO microphone stands, NO speakers, NO road cases, NO scenery, NO flag pole bases, NO . . . well, you should get the point).
  • To see if the automatic door closer hardware actually automatically closes the door (this is how you keep the smoke-in, air out, and keep the fire from spreading).  Disconnected, clamped, maladjusted, or broken closers must be repaired or replaced.
  • To  make sure that 'extra things' haven't been added to the door like kick-down door props (no, you cannot add these to Fire Doors!) or bailing wire to tie the door open.
  • And to check that the magnetic door release latch, if any, is properly working in conjunction with the Fire Alarm System (yes, this is the only legal way to prop a door open).

Friday, April 2, 2010

Alright, Bugsy - It's curtains for you!

Didja ever notice how Directors hate it when the theatre is suddenly flooded by light when a door is opened?  Yeah, it happens all the time.  It's really not their fault, it was the person designing the building that failed to recognize how disruptive this can be.

Denial is not just a river in Egypt.  It sometimes stems from a complete lack of admission that anyone would enter or leave a performance at anytime other than the designated time (yeah, like that's gonna happen!).

So what we get instead is folks trying to make-do.  They string-up curtain rods and cover the Exits to block the stray light.  Sometimes they cover the  EXIT  signs, too.  News Flash:  You cannot block or obscure a Fire Exit Door or Fire Exit Route.  Ref: 2010 NFPA 80, chapter 5.2.13.

Thursday, April 1, 2010

Getting NOT Kinky - Fire Curtain Release Perimeter Line

If you have a Fire Curtain in your theatre, then part of that protective system is a fire control line that surrounds the Fire Curtain perimenter on three sides (stage left, top, & stage right) and has fusible links that will separate should there be a fire in the immediate vicinity of the Fire Curtain.  That line must be a small diameter (3/8" fiber rope or 3/32" diameter 7x19 wire rope) cable so that it bends easily and move freely through the pulley blocks at the corners of the Fire Curtain.  Ref: 2010 NFPA 80, Section

The bend radius of the cable is known as the D:d ratio.  This represents the ratio of the pulley sheave diameter (D) to the cable diameter (d).  The for 7x19 stranded wire rope the recommended D:d ratio is 51:1, so the recommended sheave diameter for 3/32" diameter cable is 51 x 3/32, which equals 153/32, or about 5".  The minimum ratio is 34:1, which is means that a 4" pulley is typically used as they are commonly available.  Ref: American Iron and Steel Institute "Wire Rope Users Manual, 2nd Edition", Table 9.

In the picture above we have a variety of design issues:

  • The cable is 1/8" diameter plastic-coated wire rope.  It is a bit larger diameter than the required 3/32", so it would require an even larger sheave, about 6".  As you can see, the pulley is only about 1-1.5" diameter, or about 1/4th the required size.  This can cause the cable to 'take a set' and get a kink in it so that it doesn't want to move freely through the sheave.  I've seen wire rope as large as 1/4" diameter used with pulleys like this - and they definitely take a set after resting immobile for years on end.

  • The cable's plastic jacket might melt and gum-up the works should there be a fire - not good.

  •  Although this rigging point isn't bearing a significant load, it's still jsut bad juju to use pot-metal dime-store clothes-line pulleys, twisted-link 'dog chain', and quick-links to string stuff up.  Man-up and install it right with load-rated equipment - after-all, this is a Fire Curtain System, not just a trick-line for a one-act play!
Test your Fire Curtain System every 90 days. Ref: 2010 NFPA 80, Section
Have your Fire Curtain System Inspected Annually.  Ref: 2010 NFPA 80, Section 20.9.1.