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Fireworks

 

Bruce Morland

 

Since an early age I have been fascinated with fireworks. I toyed with “semi professional” displays for a while after graduating in 1983, but in 1990 whilst waiting for a lab experiment to “cook” during my period of research I picked up the phone to Pains Fireworks in Salisbury to ask if I could “play with the big boys”. Days later I found myself in the cab of a 7.5 ton truck driving up the M3 to fire a huge professional display for Tooting Council... I was hooked!

 

Since then I have been involved in professional displays literally all over the world and was privileged to be part of the team that won the prestigious Fireworks World Championships in Montreal in 2007. This article goes “behind the scenes” of this amazing week in my life as a pyrotechnician!

 

Firstly a small lesson in how fireworks work. Most display fireworks “throw” something into the air which either looks pretty or makes a noise! The method of the “throwing” is really the difference between the types of firework. The coloured effects are produced by “stars”. These really are the star of the show...groan! Stars are simply compressed lumps of combustible material that have a chemical composition that either makes them glow a particular colour, produce showers of sparks etc. The average star is about 1.5cm in diameter and will burn up to 4 seconds. They burn from the outside inwards and therefore it is possible to combine effects for example starting the process with a red compound then surrounding this with a green compound. When

lit the star glows green then red, accounting for many of the changing effects you see in the sky.

 

The chemistry of fireworks is actually remarkably complicated. For those of an immensely sad disposition who would like to learn more I recommend R. Lancaster, Fireworks: Principles and Practice, Chemical Publishing Co. Inc., New York (1998)

(ISBN 0-8206-0354-6). The Rev Ron Lancaster is the famous clergyman, chemistry teacher at Kimbolton School and founder of Kimbolton Fireworks. Kimbolton have been responsible for the fabulous New Year’s Eve London Eye display for the past 2 years.

 

So what about the “throwing” bit? Well there are two simple types. Let’s start with the really impressive fireworks that everyone loves to bits... the aerial shell. These are real crowd pleasers and form the bulk of any professional display.

Figure 1  shows the basic design.

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Figure 1. The construction of a typical aerial shell.

 

 

 It is essentially a spherical case made of papier mache (sometimes plastic) inside which are packed the stars. At the bottom of the shell is a small bag of gunpowder, the lifting charge. Shells are loaded into mortar tubes and a leader fuse pokes out of the top. Lighting the leader, the flame travels to the lifting charge which blows the shell out of the mortar ejecting it into the air with that wonderful stomach-punching “wallop” sound we all love! The lifting charge sets light to a delay fuse which burns through to the middle of the shell whilst it travels up in the air. After 3-5 seconds (depending on the size of shell) the delay fuse ignites a “burst charge” which set light to the stars throwing them outwards with terrific force and blowing the shell case to smithereens. Most shows we fire have 3”, 4”, 5” and 8” shells. We occasionally fire 10” shells and I have even fired 12”! The average shell travels 300-500m upwards and bursts with a radius of 100m or more. Most shells burst with a typical chrysanthemum or peony burst but depending on how the stars are packed in the shell case you can get very interesting shapes, circles, whirls, hearts, smiley face etc

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We are even starting to explore the possibility of writing letters in the sky! The majority of shells we use come from China and are all made by hand. In most situations we fire shells from racks of mortar tubes. The first shell is ignited and we then link subsequent shells together with delay fuses so we get up to 10 shells over 30 seconds with a single ignition (Figure 2).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2. Typical loaded rack of mortars. Note the shells are linked with a delay fuse which results in each firing separately seconds apart.

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The second “throwing” mechanism is candles. The principle is really much the same as the shell. The small tube replaces the mortar but the stars are still ejected by a small lifting charge. Roman candles or royal batteries have several stars stacked on top of each other and are ejected in turn, often up to 10 stars per tube burns round to its own lifting charge which blows it out of the tube igniting the next star as it goes and so o
 

We also have a number of “single shot” candles with just one star per tube. These can be really effective on buildings (e.g. the comets shooting out of Big Ben at New Year). Single shots can be linked together with fusing and clustered into boxes or “cakes” which are now the staple of many garden fireworks you buy at November. You light one end and the fusing shoots single or multiple tubes with a variety of effects/noises. We use exactly the same, but bigger versions in our displays. We have

one cake that shoots 1000 whistles in about 20 seconds...VERY noisy! Some of our big display cakes are stunning and have replaced some of our smaller aerial shells, such are their superb effects.

 

What happens with a professional display? The show is put together days or weeks ahead by one of our show designers who will have worked out effects, durations and timings if being fired to music. Let’s take a typical November 5th city council show. I normally arrive on site around 9am, check in with the organiser and do a review of the firing area, wind direction, position of barriers/crowd, fallout area etc. The fireworks arrive in a 7.5T lorry with all the equipment, and the crew (often 5 or 6 on a largish show) roll up a little later. From then it’s usually a well- oiled machine with the crew getting on with various tasks, often starting with loading the aerial shells into their mortars and positioning them on the firing site. A November show can easily have over 500 shells to load. We then usually set out the candles and cakes. For big shows fired to music we now fire everything electrically. Each firework is connected to a small electrical fuse (we’re not allowed to call them detonators!). Passing a small (9v) charge through the fuse produces a spark and the firework is lit... hopefully!

 

The latter half of the day is spent running cables to each of the fireworks and back to the firing box. It is not unusual to use over 1km of wiring on a big show! Once all is wired and continuity checked it’s time for a rest and prepare for the firing itself, check the timing of music cues, watch the weather etc.

 

Safety is our paramount concern on the day. The biggest evil is wind. The wrong direction blowing debris onto the audience is about the only reason we would cancel a show (I’ve done it twice). The butterflies start around half an hour to show time!

I’m known as Dr Ice Man by my crews as I seem to keep my emotions under wraps (doesn’t mean I don’t feel it inside)! 10, 9, 8... 3, 2, 1, ZERO, and believe me, when you hear that first firework lift when you press the first button the relief is immeasurable. During the show I’m often concentrating on my cue script, checking my stop watch and keeping an eye out for falling debris... I hardly ever see my shows!

 

The finale is always great fun, especially when you are close to over 100 shells firing in 15-20 seconds! Then that pause before...applause and whoops of delight from the crowd... adrenaline junkies eat your heart out, what a buzz! Then pack everything up and back in the van and hit the road home. Average working day 16 hours, average show time 15 minutes, average time spent watching the show less than 1 minute, average weather condition wet, cold and miserable... why the hell do I do this?

 

International Firework Championships in Montreal

 

The International Firework Championships are held every year in Montreal and companies are selected by invitation only, so we were very proud to be the first ever UK company to receive the call. The shows are held every Saturday night over July and August with a different country competing each weekend. We started work on Monday morning with the rest of the week to set our show up. We were still working on the show up to 2 hours before firing on Saturday!

 

The shows are 30 minutes duration (EXACTLY!) fired to music in a custom-built firing site on a lake within the grounds of a large funfair site (similar to Alton Towers) called La Ronde. Each show has to have a strong theme running through it and we chose “Night and Day”. All the fireworks have to be shipped out from our factory near Salisbury in shipping containers well ahead to be sure they arrive and clear customs in time. The logistics are immense but the permanent team at La Ronde seem to have nailed this over the years. Fortunately our container was waiting for us on the Monday morning and the next few days were a whirl of loading shells (several thousand), putting Roman candles and comets on frames etc. Because it was such an important display and the timings were critical we used very few delay fuses and almost all the thousands of fireworks had individual electrical fuses. The site is fortunately hard-wired but it still took 3 solid days just to connect the show together.

 

 

We knew we would have to add something special and unusual to our show to make an impact. We were up against strong competition and simply throwing lots of shells into the air wasn’t going to be enough! We have a strong tradition at Pains Fireworks of producing lancework (the firework frames that make tank battle scenes, skeletons, “Goodnight” signs etc). We decided we would build a 30m diameter “sun” which would be lifted by crane at the back of the firing siteand lit at the appropriate time. If we pulled it off it would be stunning. However this would be one of the largest set pieces we or for that matter anyone had attempted before. It was all designed, preassembled and then deconstructed back home before being transported to Montreal by ship. It took a separate small team virtually the whole week to reassemble this monster. Hearts and several other bits of anatomy were in mouths when we made the final lift with the crane to hoist it over 50m into the air on the Saturday afternoon.

 

We were ready! The music had been preloaded into our digital firing system. This was to fire over 2000 cues automatically in time with the music, firing some several seconds before they burst so that the effects were spot on the music... very clever. Continuity was good. The weather: torrential rain was forecast just at firing time! We were escorted to the side of the lake where a boat carried the entire crew waving the Union Jack to the stage. We were all introduced and presented to the dignitaries. God Save the Queen played over the speakers as we stood on the podium like Olympic champions... a little moisture in every eye... it was surprisingly emotional! Then to the grandstand whilst Mike Jones, the main show designer and leader and a small cohort of helpers went to the control centre. The rest of us took our seats and waited. The rain held and 3, 2, 1 ZERO... we were off! For a change I could watch the whole show. It was stunning! We started with daybreak and after a couple of tunes the Beatles struck up those wonderful guitar notes and John Lennon sang “Here Comes the Sun...”. The huge suspended set piece burst into flame right on cue and the audience went wild

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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The rest of the show proved to be a wonderful mixture of real artistry and suitable pace to match the mood of the music

 

We employed the set piece a second time during the night sequence to “Blue Moon” with equal effect. And so to the finale... just simply HUGE. I’ve seen many firework shows but even I was impressed with the volume of stuff we were throwing up into the air! And right on cue, right on the last note of music: silence... pause... pause... then crowd went wild! Then the heavens opened!

 

What a night. We were buzzing and despite working through the night in torrential rain (I gave up trying to keep dry and simply dripped) everyone was grinning like Cheshire cats. We then had the agonising wait over the course of the next few weeks whilst all the other companies competed since we had been one of the first in the schedule. Montreal was a dim a distant memory when in September I got the call from Pains... we’d won!

 

Yes I do sometimes wonder why I do this hobby. It’s hard physical work and I’m often freezing my whatsits off in a damp and muddy field whilst those around are having a good time and I’m (internally) stressing if anything will go off when I press the button! I often say one of the attractions is it’s totally different from the day job, but I’m not so sure. It involves working with a highly professional crew, get it wrong and the consequences are devastating, get it right and the rewards and feedback from the public are immense. At the time of writing this article we have two opportunities to display the fine art of pyrotechnics in 2012, the Diamond Jubilee and Olympics... I hope to be there... “light the blue touch paper and retire!”