Market Guide for Purchasing a Driveway Gate
& Driveway Gate Automation
Contract
A good contract will cover most aspects of an installation. Important
details to look for are: written completion date; site clean up;
responsible party for supplying power and communication lines to
the gate; permit fees, if needed; amount the contractor charges
if he obtains the permits; hidden conditions clause, i.e., extra
costs associated with the discovery of buried boulders, tree roots,
utility lines, or unsupportive soil conditions.
Contractor
Your contractor must be licensed, bonded and insured, and have compensation
insurance for his employees. A contractor can easily supply you
with proof of all the above, so don’t hesitate to ask. You
will usually get two out of three of the following qualities in
a contractor: price, quality, and timeliness.
Bid comparison
Start with a reputable, well-known firm. Obtain a bid that is all-inclusive
and then have other contractors bid on the same items. Compare "apples
to apples". This is a good way of leveling the playing field.
The lowest bid is not always the best bid.
The complete job
Job site safety, gate drawing, site plan, soil stability check,
posts, footings, grading, gate, electrical and communication supply,
entry system, fire medical emergency lock, gate operator, exit loop,
safety loops, photo electric eyes and other safety equipment, lighting,
site cleanup and restoration. All these items will be explained
in the following paragraphs:
Job site safety
The job site has to be safe. All excavated areas need to have cones
or barriers. Protruding reinforcing bars, "rebar", need
to be plastic-capped. All garbage has to cleared away and all dangerous
areas cordoned off.
Gate drawing
The purpose of a drawing is to see the gate as it would appear when
finished. It should include any posts, columns, and lighting. It
is also good to see the side-to-side slope of the road, as it would
appear under the gate. This is especially important if you have
a lot of slope. The width of the road should also be included. A
gate drawing is usually required when obtaining a permit.
Site Plan
The site plan is important for showing the location of both the
gate and operating equipment. A good plan will show where all the
wiring is buried and is useful for future repairs and any excavating
you may want to do later. A site plan is usually required when obtaining
a permit.
Soil stability
If the soil is not stable there is a good chance your gate will
sag. Soil conditions are the first thing to look at before you begin
your project. If soil is not solid or has major clay content you
will need additional structural support. You may need a grade beam
or outriggers. Grade beams are concrete beams that connect both
posts or columns together below grade. Outriggers are metal arms
that extend out in the two directions the gate swings and are anchored
in concrete. Post-holes have to be square or the swinging motion
of the gate will eventually enlarge the holes and your gate will
sag.
Footings for columns
Concrete footings are required if you plan on installing columns.
The column footing needs to be installed at the time of the gate
installation. Footing size is determined by column size and soil
condition. If the soil is firm and stable the footing must be at
least 30 inches down and be at least six inches wider than the proposed
column on all sides. If the soil is loamy, clay, or sandy then go
shallow and wider on the footings. A typical shallow, wide footing
for a 30 inch x 30 inch column would be a 60 inch x 60 inch wide
hole, 18 inches deep, with 12 inches of concrete and rebar. It may
be necessary to connect both footings together across the driveway
with a grade beam.
Underground Service Alert
Make sure that either the contractor or you call for an underground
utilities check before excavating. In most areas this removes liability
if the contractor should cut through a buried utility line. The
various utilities come to your job site and mark all underground
utilities, usually at no cost.
Posts
Steel posts can be either those that flank the gate on each
side or internal steel "skeletons" that are imbedded in
masonry columns. The skeleton sets in the middle of the column footing
and is used to hold the hinges, gate operators, equipment vaults,
and lighting.
Gate posts should be at least 5 inches x 5 inches and set 36 inches
below grade. The minimum width of the hole should be 20 inches x
20 inches and contain a minimum of half a yard of concrete. The
holes should be square to prevent loosening by the gate’s swinging
action. For further illustration, see "Anatomy of a Gate".
Grading
Some sites are flat. Those that are not may need grading. Water
flow should be considered when grading. All added road base has
to be compacted.
Gate
Heavier gates have a tendency to last longer. Where hollow tubing
is used it should be of a heavy gauge. The frame should be of at
least .120-inch wall thickness and stakes should be at least .075
inch thick. The gate must have weep holes to allow trapped moisture
to vent or the gate will rust from the inside out.
All weld slag must be removed before painting or powder coating.
Removing slag is a tedious process. If not done thoroughly, it is
a major detriment to the longevity of a gate. Since paint does not
get into all the tiny spaces surrounding the slag, it later falls
off leaving a bare spot where rust begins. You can tell good workmanship
by how smooth the finish feels when you run your hand over it. Check
the areas around welds, and check several gates built by your prospective
contractor for this quality.
Powder coated finishes are superior to enamel and can last up to
15 years. A good enamel paint job will last up to six years. Single
coat paint jobs, also called primer paints, last only two years
at best and should be avoided. Galvanization should be considered
if you live near salt water. You may powder coat over galvanization
if you prefer a different color.
Electrical And Communication Lines
National electrical code calls for electrical lines to be buried
at least 18 inches underground. Unfortunately we often find these
more shallowly placed. It is not a pleasant experience if you hit
a power line. Even if you don’t get shocked you will endure
a costly underground splice.
Power and communication lines should be spaced at least six inches
apart. This prevents noise on your telephone or intercom system.
The conduit should be larger than necessary for easy wire pulls
and future repair. The wire should be large enough to deliver the
needed current after line loss. Line loss is a voltage drop that
happens whenever power is delivered over long runs. Almost all underground
conduit fills up with water. Use wire with appropriate insulation
to hold up to these prolonged conditions.
Most single gates (one operator, or motor) need 10 amps at 110 volts
AC. Consult an electrician before laying long runs underground so
that you get the right gauge of wire. Splice or "Christy"
boxes, should be installed at least every 200-300 feet. Use high
quality communication wire, preferably direct burial cable installed
in conduit.
Entry System
There are many entry systems on the market, many of which are
good, though some are more difficult to program than others. Check
with your installer on ease of programming. We use DoorKing products,
as they are top of the line and easy to work with. Determine whether
you need a simple keypad or one that communicates through your telephone
system. There is a large cost difference between the two. Card reader
units are used more in industrial applications and multiple dwelling
communities. Make sure the "Goose neck" or pedestal mount
is sturdy. The unit should not move when you use the keypad.
Fire Medical Emergency Lock
Most municipalities require you to have an emergency lock to
allow emergency crews to enter your property without damaging your
gate or automation equipment. Make sure this item is not left out
of your installation; you will only have to install it later.
Gate Operator
There are several ways to operate a gate. Swing gates can use
three types of operators. A swing arm operator, which is a box,
that sits off to the side and has an arm extending to the gate.
A ram arm is located on the gate and post and uses either a hydraulic
piston or a jackscrew-operated piston. Underground operators are
located by the hinge and operate the gate from below grade.
The simplest to service and install is the swing arm operator. The
advantage of the ram is that it is smaller and takes up less space.
The underground operator is the most expensive but is very attractive
in that you see no equipment. The swing arm is usually the fastest
of the operators. The DoorKing units open a gate in five seconds
and are the fasted units on the market. The swing arm units also
handle a gate very smoothly and slow down toward the end of each
cycle. Most ram arms do not have a slow down cycle and the gates
have a tendency to shudder at the end of each cycle. This shuddering
is more pronounced when the gate is longer as in a single swing
gate installation.
Slide gate operators are commonly installed at the end of the gate
in the closed position but can also be installed by the end of the
gate in the open position. A chain is attached across the gate near
the bottom and passes through the operator, which shuttles it back
and forth. In the end of the gate/open position you do not see the
chain or any operating equipment near the gate. Sliding gates are
more hazardous than swing gates and should be equipped with appropriate
safety devices.
Either type of gate operator is available in 110 volt or low voltage
DC operated. The DC powered gates can run off low voltage transformer
or solar panels. Solar installation requires more maintenance than
an AC powered system. Solar should be used only when it is not economical
to bring AC to the gate. Quality operating equipment will last from
12 to 20 years before it needs to be replaced, depending on use.
Most installations use a built-in timer that closes the gate after
a set period of time
Exit Loop
An exit loop is wire that is either buried beneath the driveway
or cut into the concrete or asphalt. It is located behind the gate.
Locating it far from the gate is best. A vehicle triggers the loop,
which acts like a big metal detector and opens the gate, allowing
the vehicle to exit.
Loops are a weak spot in many gate systems. All loop connections
must be soldered and any underground connections completely waterproofed
in order to avoid problems. The size, shape, and number of turns
of wire in the loop will determine the sensitivity. Loops cut into
asphalt or concrete should be 1" or more deep. Those buried
in earth or gravel should be 4-6 inches.
Safety Loops, Miller Switches, and Photo Eyes
"Safety" loops are buried or cut in the pavement in
front and behind a gate. They prevent the gate from closing on a
vehicle in its path should it stay there past the "momentary
open" timer setting.
"Miller edge" switches, long strip switches as found on
elevator doors, are required on slide gates at each end to prevent
entrapment.
Photoelectric "eye" and safety loops are often used in
combination with one another.
A single photo eye may be used on a slide gate to hold the gate
open in case a vehicle stays too long in its path or reverse if
a vehicle enters its path as it is closing. Other "entrapment
zones" created by the gate, i.e., sliding behind a fence or
wall, require a photo eye as well.
For more information refer to our section on regulation U.L. 325
safety guidelines.
Finally, all gates require a warning sign, visible from both sides,
to prevent accidents and limit your liability.
Lighting
Lighting often is located either on top of gate posts or on
top or on the front of columns. The best way to control lighting
is with a combination timer-photocell. The timer is set to activate
in the afternoon and has a photocell located between it and the
lights. Once the timer is activated, the photocell prevents the
lights from coming on until dusk. The timer shuts off the lights
at a predetermined time, i.e., midnight. In this way the lighting
tracks the seasons and you do not have to keep adjusting the timer.
Site Cleanup
A project is not finished until the job site is thoroughly cleaned
and restored to its former state. Special circumstances should be
discussed, i.e., hauling away certain debris. It should be made
clear whose responsibility this is. The contractor should always
perform ordinary clean up at the end of each day. |
