Back to Facility Manager
Contents
Back to
Home |
 |
|
Kansas State is one of the
first facilities to utilize barrier jackets for media attention. |
A
Wind - Wind
Situation
By Murray Bilby
This article will address the issue
of wind resistance on temporary portable railings such as steel
barricades, and the related issue of how wind can influence the
stability of the barrier by using accessories such as jackets, banners,
covers, and signs.
 |
|
As with standard frames,
proper utilization
and planning can allow the high frames to be
used effectively even in windy areas. |
Background
Steel barricades (as well as plastic variations) are well established as
an effective crowd management tool. Most public assembly facilities
maintain an inventory of steel or plastic barricades.
Increasingly, signage is being attached to barricades. Messages or
images through signage can increase an event’s safety by providing
patrons with directions, rules, or other information. Additionally,
barrier jackets or banners often work as advertisements by featuring the
logo of an organization or sponsor.
Blowing In The Wind
Messages on jackets, banners, or metal signs demonstrably
add value to a portable barricade. However, there is an issue – albeit a
minor one – regarding whether these accessories add wind resistance,
thus making a barrier more susceptible to tipping over in windy
conditions.
If a sailboat can still race with torn
sails, then we need to make a similar analogy to a free standing
barrier. Adding additional resistance with signage will clearly be an
influence.
This is a concern that any facility or event manager should be aware of
when planning to utilize steel or plastic barricades (and their
corresponding jackets) in high-wind situations. But the addition of a
jacket, banner, or sign to a barrier is only one factor which impacts
the stability of these barricades in windy conditions. Here is a rundown
of other factors which also play large roles in ensuring the
wind-stability of barricades.
The Wind Factors
The Product: First and foremost,
barriers can – and sometimes do – blow over. It is inherent in the
product. Steel barriers are designed to be temporary railings, easy to
set up and take down. At most locations, barriers are more likely to be
used individually, or in short non-connected lines, rather than being
hooked together in longer interconnected lines (like the traditional
Mardi Gras parade lines). A running line of frames improves stability,
but even when hooked together, barriers can still be knocked down by
heavy winds.
Quality: Barriers of differing qualities exist, even though
differences (some of which are done for cost-cutting reasons) may not be
easily noticed from a photograph. Variations can include different
materials (steel, plastic, aluminum), weights, diameters, height, and
tubing styles.
Center of Gravity: Plastic
barricades, as well as some new steel barrier variations, have higher
centers of gravity than traditional steel barricades. While these styles
offer some advantages, stability is not one of them.
Base Style Factors
a) Square stacking variations:
Inherent in the design of square stacking barriers is a single pivot
point where the tubing edge meets the ground. With less ground contact,
when the wind blows, the top can arch over and fall sooner than would be
the case with other base styles.
 |
|
The main ticket entrance
of Radio City Music
Hall includes several hundred barriers to help
stage visitors on both sides of the building. |
Additionally, some square stacking
variations have just a 9-inch spread between ground contact points.
Traditional frames (including the Blockader square stacking unit) have
24 inch spreads, yet are still susceptible to wind gusts. The higher the
center of gravity the wider the base needs to be.
b) Barriers with
traditional base on one end; single tube (insert) on other:
This style has advantages in handling and cost reduction. However, when
struck with a strong gust of wind, this style in lengths over 4 feet
will tend to turn over more easily than even the square stacking
variation, because one end will only have the width of the tube (1.5
inches or less) touching the ground.
c) Traditional bridge bases: The
traditional double bridge base style, with its egg-shape ground contact
points, remains the most popular style and represents half the market.
This is due in large part to its stability.
d) Flat bases: Flat bases also
provide stability, because they will tend to slide, rather than tip
over. Rubber inserts increase ground friction by adding more resistance.
Flat bases are most effective in wind, because they can be anchored to
the ground through holes via tent pegs.
However, flat bases have a tendency over time to curve at the neck,
creating a rocking chair effect. Handling flat base barriers with care
(especially avoid dropping them from a height to the ground) will give
these bases longer effective life-span.
Real Stability Solutions
To alleviate any concerns about the stability of temporary railings in
windy conditions, here are the most practical steps a facility or event
can take:
1) Use high-quality barriers and bases.
Get to know the industry standards for barrier quality, and understand
the advantages and disadvantages of the various base styles. Traditional
bridge bases, and flat bases, are the styles that provide the most
stability in wind.
2) Place your barriers in zig-zag arrangements.
A zig-zag line creates more ground resistance and wider base support. We
have been told that this solution has been successfully utilized at
helicopter pads.
 |
|
Here is an example of
correctly sandbagged
units with signage. |
 |
|
Wind cuts can be
unobtrusive when spaced
around printed text in reducing resistance. |
3) Add anchors
or sand-bags to barriers. When it comes to reducing the force
of the wind, this is a time-tested option to improve stability and
decrease the risks of barriers tipping over.
Wind Cuts?
A banner, jacket, or sign adds additional resistance to
wind and can increase the risk that a barrier will blow over. But
because of the misconception that this is a significant stability
factor, some barricade owners have inquired about the possible
advantages of wind cuts (sometimes also called half-moon cuts) to their
jacket or banner.
Wind cuts are only a minimally effective solution to any potential wind
stability problem. First, the vertical uprights of the barrier will
prevent most cuts from opening properly, and unless cuts are perfectly
aligned on both sides of a jacket, any wind that does get through will
be trapped between the two sides.
In addition to not working on a practical level, cutting a banner,
jacket or sign defeats its purpose. Images or messages will no longer be
attractive and effective if they are riddled with holes.
Consequently, we do not suggest or promote wind cuts on the jackets we
design and market. We will do it on request – at no additional charge –
but we always encourage more effective solutions.
Conclusion
Jackets, banners, or metal signs expand the utility of
portable railings. Steel barriers can serve their intended crowd
management role, while a jacket’s ability to convey messages on a
barrier has proven to be a great communication and marketing tool for
many facilities.
The addition of such covers to a barricade is one of several factors in
contributing to the barrier’s possible instability in windy conditions.
The most effective way to ensure barrier stability in windy conditions
is to make sure you use quality barriers and bases, plan the proper
arrangement of your barriers to adapt to the conditions.
Murray
Bilby is president of The Tamis Corporation, supplier of Blockader
barricades and accessories (including custom-fit barrier jackets). For
more details and illustrations, an expanded version of this article will
soon appear on the blockader.com
Website. |
|
