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It would be fair to say the guide sparked a

lot of fairly passionate debate and in some

cases vehement opposition. This was to

be expected; we were changing a guide

that had been in place for nearly five

years and in some cases recommending

over double the requirement.

It was therefore interesting to read

the fantastic article written by Maura

Paternoster in the American Rental

Association (ARA) August 2016 edition

of

Rental Management

. Maura is the

risk manager for the ARA and the article

was an in depth study of how companies

approach weighting and hold down of

tents/marquees in North America.

An interesting observation in the first

section of the article really caught my

eye: “It is only luck that improperly

secured tents and the people and

property around them, survive without

incident, but every time it happens it

reinforces a false sense of confidence and

perpetuates a risky practice borne from

inexperience.”

This is a very powerful statement and my

agreement is total, however I would go

even further. It is human nature to rely on

past experience. No one willingly wants

to do the wrong thing however each time

we get away with something we learn

bad habits. Every time we unknowingly

or wittingly underweight, even if luck

is on our side, we move a step closer to

disaster.

As indicated the article looked at the

various methods for holding a tent/

marquee in place, exploring the accepted

practice and providing reasons why

erectors adopt this practice.

In summary the rule of thumb for them (in

the US) is 10lbs (4.5kg) of weight for each

square foot (0.09m

2

) of fabric. It should

be noted this is for a weekend only. If the

tent/marquee is in place for longer, the

rules change to 15lbs (6.8kg) per square

foot.

This is very interesting and it shows

our Australian guide compares very

favourably. Since the article in the ARA

Revising the weight on our minds

By Tom O'Dowd – National President – Events

The HRIA recently updated the revised weighting guide; this was an update from the

guide's launch in May of last year. The revised guide adds a number of explanatory photos

and a new addition to the tables providing an option for a lower wind speed.

magazine only looked

at a marquee or tent

with all walls open

(no side walls) we can

compare this to our

HRIA guide in the

following study.

For comparison we

have used the LBS

per square foot model

and then converted

the end result to

express the ballast in

kilograms.

USA

10ft x 10ft = 100ft

2

x 10lbs per ft

2

=

1000lbs. This is 450kg

for all four legs.                

(10ft x 10ft is

equivalent to a 3m x

3m).

20ft x 20ft = 400ft

2

x 10lbs per ft

2

=

4000lbs. This is

1,812kg for all six legs.

(20ft x 20ft is equivalent to a 6m x 6m).

HRIA

3m x 3m = 9m

2

. Our guide calls for (all

walls open), 90kg per leg x 4 legs = 360kg.

If we have one or more wall open then

the force is multiplied by the factor of the

walls and we call 460kg per leg.

So in the case of a 3m x 3m with three

walls (one wall open) based on the

amount of fabric, looking at it from the

USA perspective:

100ft

2

for the roof = 100ft

2

;

70ft

2

for each wall x 3 = 210ft

2

;   

Total - 310ft

2

x 10lbs per ft

2

= 3100lbs.

This converts to 1,404.3kg.

Divide this by four legs and we get 351kg

per leg. Our guide calls up 460kg but is

based on a minimum one week duration

(this is clearly identified in the notes). The

minimum that can be calculated is one

week in accordance with the Temporary

Structures Standard. Adopting the USA

rule of 15lbs per square foot they would

use 4,650lbs or 2,106kg divided by four

legs = 526kg per leg (66kg more than us).

6m x 6m = 36m2 Our guide calls for (all

walls open) 170kg per leg x 6 legs =

1,020kg. If we have one or more wall open

then the force is multiplied by the factor

of the walls and we call 640kg per leg. So

in the case of a 6m x 6m with three walls

on the amount of fabric, looking at it from

the USA perspective:

400ft

2

for the roof = 400ft

2

;

140sq ft each wall x 3 = 420sq ft;    

Total – 820ft

2

x 10lbs per square foot =

8,200lbs. This converts to 3,714.6kg.

Divide this by six legs and we get 619kg

per leg our guide calls up 640kg – again

based on a one week duration.

I am sure by now some of you are

thinking the winds in the USA are much

greater than the suburbs of Australia. We

The HRIA recently updated the revised structures weighting guide

46

HIRE AND RENTAL NEWS •

EVENTS in FOCUS

• FEBRUARY 2017

EVENTS in FOCUS