Most emergency services personnel realize the convenience and cost savings associated with trailers in everyday life. Need to haul a load of firewood? Buy a trailer rather than a pick-up and save thousands of dollars at the point of purchase.

So why are trailers not considered more seriously by most emergency services providers? Apparatus in many cases costs hundreds of thousands of dollars, while trailers list at a fraction of that cost. When considering additional cost savings such as maintenance and insurance trailers are an extremely cost effective alternative in providing some services. Obviously trailers are better suited for services which are necessary but are only provided on an occasional basis.

We will look at everything form baseline trailers used

to transport equipment to top of the line mission specific units. This will include trailers up to 48’ in length and not exceeding 18,000 pounds GVW.

Let’s consider some simple math, say you need a mobile command and communications center, you spec a unit and are quoted upwards of $300,000 or more. Now look at the trailers numbers, a good quality trailer outfitted with a similar configuration may run you $150,000. Throw in a good quality tow vehicle at $30,000 and you just saved $120,000 Look too at the versatility of the tow vehicle; you now have the “Power Plant” to tow other trailers, expanding both your fleet and it's capabilities. Following this example may even allow you to provide services you could not previously do to budget constraints.

Next example, you need to transport additional hand tools and equipment for wildfire response. Again the call rate is small but your geography requires you to provide this service. The brush truck you currently operate is not

Foster Rescue's ARU-285 Rescue Trailer

 large enough to carry the additional items. Your choices are a Heavy-Duty Pick-up truck at $30,000 or a tandem axle enclosed trailer towed by your current brush truck at $5000. Which makes the most sense?

Services such as Hazmat Response, Personnel Rehabilitation, Wildfire Supply, Mass Casualty, Mass Deacon, Foam Deployment, USAR, Technical Rescue and Special Events Coverage can all be handled efficiently with trailers.

Check out the examples in the Pa Firefighter Trailer Idea Gallery

Towing is not limited to trailers only, in recent years a number manufacturers have started offering tow behind emergency equipment. Everything from fire rated pumps to USAR rescue units complete with air, electric power and hydraulic rescue tools are now being offered to emergency service providers. One manufacturer even offers a mobile breathing air station complete with compressor.

Wel-Fab Mobile Decontamination Unit Deluxe

The Tow Vehicle
Anyone who has not towed a trailer recently can not fully appreciate the advancements in the modern towing industry. The big three auto makers all offer heavy duty tow packages which integrate necessary functions such as lighting and braking into the vehicles own systems. Should your vehicle not have all the needed tow functions they can easily added. Most equipment can be added with simple plug in units which require no alterations to your vehicle or it's wiring.  Setting up your tow vehicle need not be a huge expense, in some cases this could allow for multiple tow vehicles from your existing fleet.  An example of tow vehicle setup cost is displayed below, this example outlines the set-up cost for a 1 ton pick-up truck towing a trailer up to 12,000 pounds GVW.

Item	Detail or Specification	Cost
Hitch	Draw-Tite 12,000 lb Ultra Frame	$401.00
Brake Control	Tekonsha Powertrac 1-2 Axle	$59.95
Light Connection	Std 7Way RV Plug w/ T-One Connector	$36.95
Accessories	Draw bar, balls, pins etc	$49.95
Labor	To install above	$65.00
	Total	$612.85

Rates in your area may differ

Be sure to match the tow vehicle with the trailer size. I would not recommend any vehicle rated below 1 ton for any trailer rated at or above 7000 GVW. If in doubt follow the vehicle manufacturers’ specifications on towing.

Brake Controls
Modern solid state trailer brake controllers are extremely reliable and very easy to operate. The trailer brakes are applied automatically with the tow vehicle brakes at a predetermined rate which is easily adjusted by the driver to match road conditions. There are even units which are activated via inertia and do not require tapping into the tow vehicles system. Many models have self diagnostic features which enhance safety with immediate system condition notification. All units include a manual brake application feature allowing the driver to apply the brakes to the trailer only. This function is ideal for steep grades, bad weather and evasive maneuvers.

Common Trailer wiring and brake components

Lights and Wiring
With out a doubt wiring to a trailer can be one of the most frustrating issues in towing. A little care and some preventive maintenance can eliminate most if not all wiring problems. Be sure the wire gauge is heavy enough (or better yet heavier) to carry the electrical load placed on it. Also make certain every circuit is protected by a fuse or breaker. Brake control circuits should be protected by a self-resetting circuit breaker. Doing so allows protection to the wiring while supplying short intervals of brake system operation for safety.  All connection points should be clean and free of corrosion. Anti-corrosive cream products are available from several manufacturers and do a great job of protecting the plug and socket.

SAMPLE TRAILER LIGHT WIRING DIAGRAM

The trailer plug should always be stored up off the ground to aid in corrosion resistance.

When setting up the tow vehicle try to add at least two additional circuits to your trailer for future expansion. You will most likely use one right away for warning lights.

Hitch Options
In this class of trailer there are three hitch options, two of which use a system mounted in the bed of the tow vehicle, the other is mounts to the frame and extends out the rear of the tow vehicle.

The frame mount hitch is the most conventional and normally referred to as a receiver hitch or a ball hitch. It utilizes a heavy duty hitch/receiver assembly which mounts to the frame of your tow vehicle and extends out the back via a square shank removable drawbar. Most heavy duty 1 ton class vehicles come from the factory with a receiver hitch already installed. Be sure to check the hitches rating, some are rated at only 5,000 pounds. Heavy duty receiver hitches up to 12,000 pounds are available aftermarket. I highly recommend you install the 12,000 lb version regardless of the trailers actual GVW. The industry generally recommends receiver  hitch only be used with trailers under 12,000 pound GVW.

Please Note: No trailer, regardless of weight, should ever be towed utilizing the holes commonly found in step or pick-up bumpers

Be sure to use only high quality towing products

Sway control by Draw-Tite

Two towing enhancement are available for receiver style hitches. Weight distribution hitches give you a noticeably smoother ride by controlling sag plus virtually eliminating bounce at the hitch. This aids in driver comfort, confidence and improves the overall safety and control of the entire rig. Additionally a sway control unit helps control the effects of air movement from large vehicles passing you at highway speeds, cross wind and axle tracking issues. If you are acquiring an enclosed trailer 16ft or longer weight distribution and sway control are both highly recommended regardless of the trailers GVW.

A few heavy duty products commonly used in towing loads over 10,000 lbs GVW

The bed mount hitch choices include the fifth wheel hitch. This is basically a scaled down version of the units found on heavy duty over the road tractor trailers. These units mount in the bed of the tow vehicle by passing through the bed and fastening to the vehicle's frame. A number of options are available in this type of hitch including sliders, tilt units and air assist. Fifth wheel hitches generally top out at 22,000 pounds GVW.

The alternate bed mount hitch choice is commonly referred to as a goose neck. While the hitch mounts in much the same location and the same way as the fifth wheel it uses a ball to make the connection to 

the trailers. This system is very common in agriculture and livestock trailers and can be rated as high as 30,000 pounds GVW.

Both bed mount hitch systems typically can be removed our stowed to allow convention use of the vehicle. They also dramatically reduce the turning radius of the truck/trailer combination by locating the connection point in-line with the rear axle of the tow vehicle. These units would typically be considered for trailers over 10,000 pounds GVW and 24’ or longer in length.

The location of the load on a trailer will affect the ride characteristics. Too little load on the hitch can cause the trailer to wander or sway. Too much hitch load can overload your towing vehicles suspension.

The Trailer
Now let’s look at trailer construction features. Trailers are like any other vehicle in there is a number of manufactures all with their own options and construction methods using different materials.

Axles and suspension
I rarely mention manufacturers by name in my articles. But, when it comes to trailer axles and suspension components there is only one manufacturer of axles worth a mention. Dexter Axles are without a doubt the only equipment you should spec into your personal or emergency services trailer.

There are 3 suspension systems widely used in the trailer industry.

First and the most familiar is a leaf spring hanger configuration. This system uses multi-leaf springs attached to the trailers frame via shackles and center equalizer links. While this is a strong, time proven system it does show wear faster and is significantly noisier than the other two systems. It should be noted however this suspension system does allow more wheel travel then its counterparts leading itself to extreme off road applications.

An example of a basic Leaf Spring and Hanger Axle

Second offering is a torsion axle. This axle uses no springs but rather a torsion bar set in a rubber compound. These axles are extremely smooth running at highway speeds due in part to each wheel being totally independent from all others on the trailer. The rubber compound allows far less road shock to be transferred in to the trailers body as well. Torsion Axles are available in many different ride heights allowing for the lowest deck offering of the three systems mentioned. Other than the hub and brake assemblies these axles are maintenance free and easily to replaced. Should a bad axle need to be swapped out simply remove 4 bolts, the brake lines and the axle will drop right out. One draw back is limited wheel movement; the torsion system allows only a few degrees of movement therefore off road operations must be conducted at reduced speeds.

An example of a Dexter Torflex Torsion Axle

Lastly is air ride or pneumatic cushion systems. Basically an air bag replaces the metal leaf springs. While somewhat complex this is the Cadillac of trailer suspension systems. Super Smooth, with the ability to dial in the suspension to match the current load and road conditions this system is truly a perfect solution. There are even kits available to convert your existing trailer from leaf springs to air ride. But, before you commit to air ride consider two points, it’s twice the cost of other systems and the tow vehicle requires special equipment, such as air compressors and valving which may not be used for other trailers in your fleet.

An example of a Dexter Airflex Torsion Axle

My recommendation? If your specs call for a suspension system rated at less than 10,000 lbs go with the torsion axle. Anything heavier consider torsion but go with an air system if your budget allows. If a considerable amount of your responses will be on rough, dirt roads or even completely off road go with the spring and hanger system regardless of GVW.

Please Note, the industry does have a few manufacturers using axles acquired from mobile homes. These axles typically are not built for repetitive use. Buyer Beware

The Dexter EZ Lube hub allows easy lubrication of the wheel bearing. Note the way the grease is channeled, pushing old grease and dirt from the rear and out the front.

Hubs, Tires and Wheels
Here proper components are crucial in setting and maintaining the GVW rating of the trailer. Other then rim design you most likely will not have many options to choose from with these components. My best advice is to follow the designer/builders recommendations.

Check wheel fastener torque frequently. Each time a wheel is removed and re-mounted, the lug nuts should be checked and re-tightened after ten (10) miles, twenty five (25) miles and fifty (50) miles and periodically thereafter.

Radial Tires are the norm for trailer operations and should be the only accepted tire option on your trailer. Beware Bias Ply tires are still available and may be standard equipment on some trailers. Tires are rated via “Load Range” which is clearly marked on its sidewall. This is referring to the number of  

plys built into the tire and indicating how much load can be placed on the tire horizontally. This is important because trailer tires don’t turn, they scuff and scrub as the vehicle turns applying heavy loads to the side wall of the tire. You will most likely be dealing with a Load Range C which is 6 ply, Load Range D or 8 ply and Load Range E or 10 ply on this class of trailer. Always make sure the tires on your trailer are inflated to the proper air pressure as specified by the tire manufacturer. Also be sure to have your tires rotated and balanced according to the tire manufacturer's recommendations 

If possible select the largest diameter tire offered. The larger the diameter the slower the wheel bearing speed thus a longer bearing life. Larger tires also enhance rough and off road operations by rolling over holes and deformations rather then dropping into them.

Use the proper wheel fastener and torque range as specified by the wheel manufacturer. Excessive torque can permanently damage the wheel while insufficient torque can result in stud failure. Most custom aluminum cast wheels require special lugs, one of which may even be a locking unit. Use only the lugs designed for this type of rim or rim failure will result.

Remember to have wheel bearings maintained regularly to as stated in your Operation & Maintenance Service Manual assure reliable, long life performance. This service should be done annually as a minimum

Make sure there is enough clearance around the sides and top of the tires to prevent the tire from rubbing on the frame or other trailer structure.

Braking systems
Check your brakes before every use to make sure they are functioning properly. This is easily and quickly accomplished by applying the trailer brakes manually and trying to pull forward, you should feel a heavy resistance.
Not all trailers are going to have a breaking system. In Pennsylvania brakes nor state inspection are required if the trailers GVW are less than 3000 pounds. This would usually reflect a single axle unit used to carry light materials.

Have brakes installed on any trailer which will be used for emergency response regardless of weight. Brakes will have a huge impact on safety especially when it comes to the evasive maneuvers which are inevitable when emergency services encounter civilian drivers.

Trailer braking systems can be self actuating or remotely actuated. Self actuating systems are a hydraulic arrangement which uses the trailers kinetic energy to apply pressure to the brake system. While this type of system may have its place, emergency services are is not it. Enough said.

Let’s concentrate in remotely actuated systems. These systems use an electric signal from the tow vehicle to apply the brakes. The brake control unit is tied into the tow vehicles brake system to allow for simultaneous brake application with the tow vehicle. The system also allows for rate of application and power adjustments as well as a manual system which can be used to apply only the trailers brakes. Once the electric impulse reaches the trailer it applies one of two types of systems on the trailer itself. First off is an electric/magnetic system (Shown to right). The electrical power energizes a magnet which applies the brakes. Don’t let this systems simplicity fool you, electric brakes are powerful and dependable if maintained properly. Electric brakes do however limit you to drum style brakes. An example of an electric trailer brake system can be viewed  HERE

A typical electric brake assembly

The second system uses the electric impulse to activate what is accentually an electric master cylinder which supplies hydraulic power to the braking system. This system is very similar to your automobiles brake system and is available in drum or disc configurations. You should request this system with disc brakes on heavy multi axle trailers rated above 12,000 pounds.

All brake system types have a break-away safety mechanism. This unit applies the brakes to the trailer should it become disconnected from the tow vehicle. Some of these units utilize a 12 Volt Lead-Acid battery mounted on the trailer the condition of which needs to be checked regularly. Regardless of the type of break-away system it must be checked for proper function every time the tow vehicle and trailer are connected. Break-away systems should NEVER be used as a parking brake.

While air brakes are used heavily in over the road trucking, the system is rarely encountered in this class of trailers towed by non-commercial vehicles.

Remember to lubricate the moving parts in your brake system per the manufacturer’s recommendations. Proper maintenance will prevent them from seizing up. Do not allow grease or oil to contaminate the linings, drum surfaces or magnets.

Remember that new brake shoes need to be burnished or "seated in". This process may take quite a few stops to get the shoes fully worn in before maximum brake performance can be achieved.

Frame Construction
There are only two material choices for trailer frames, steel or aluminum, The only reason to choose aluminum is weight as corrosion can actually be worst with aluminum frames in northern climates where road salt in used. Whether steel or aluminum frame rails specify box channel construction for added strength.

Sidewall Construction
Trailer sidewalls are typically aluminum outer skin with rough or finished plywood inter skin as a basic configuration. The outer skin in most cases is a pre-finished permanently colored aluminum product which does not require painting. Unfortunately this limits the color selection. While painting and color matching is

A see through construction example by Haulmark Trailers

possible it normally comes without warranty and may not even be offered by some dealers. If painting is necessary be sure the company doing the work is well versed in the prepping and painting of aluminum to prevent future problems or find a manufacturer which offers a steel skin product as an option. I’d strongly recommend using a stock color with the factory baked finish.

The wall studs are offered in wood and steel with aluminum offered by only a few manufacturers. Each has its benefits and drawbacks. Obviously metal offerings are going to be stronger but can be a hassle when it comes time to customize the interior. Wood may not be as strong but eases the alteration of the sidewalls. Wood rot is also a consideration should the trailer start to leak. If you are not altering the sidewall or are purchasing a trailer with a preconfigured, refinished interior go with metal studs.

Doors and Windows

You will most likely find a need to have non-standard doors and windows installed on your trailer. All trailers have a rear door with trailers of 16 feet or more normally offered with a curbside man door as standard equipment. Rear doors come in two basic configurations side opening cargo doors or lay down ramp doors. Each has it's own obvious use and benefits. Match your doors to your use. If you have no use for a rear doors on your mobile command center or communications vehicle consider adding them anyway. They are standard equipment, so they don't add to the units cost additionally, they add to the units resale value and  the trailers future flexibility. Additionally should a major re-configuration to your trailers interior be necessary a large rear door may come in handy. Also consider the type of door before ordering. Trailers are offered with cargo style doors which are the standard offering or what are commonly referred to as RV doors. The cargo doors are in most cases manufactured by the trailer builder out of the same materials as the trailers sidewalls.  The closure is normally a cam style with

RV style components installed on a cargo trailer

a padlock hasp. This does not allow for the latching or unlatching of the door from inside the trailer. RV doors come pre-hung normally from an outside vendor. They commonly have windows, are insulated with a all weather seal, and can be opened from both sides.

It's rare to find windows offered as standard equipment. Consider the need for windows carefully particularly in regards to safety. Should you decide to add windows use slide opening RV style windows. I recommend against crank-out or louver style windows.  Once installed  the protruding frames generally end up head or neck height on the exterior of the trailer making them a safety hazard. This in an area which is usually a very busy place. Slide opening RV windows are offered by most trailer manufacturers as an option, they include insect screens and look quite good

If you have no preference as to the type of rear door on your trailer go with the ramp style, they make the trailer more useful and add to it's resale value.

Flooring

Most trailer floors are plywood or wood plank. In the case of enclosed or cargo trailers the floor is usually painted plywood and may include an anti-slip feature. You can customize trailer floors with just about any floor covering found in the building construction trade from carpet to asphalt tile to hardwood. Please note that masonry flooring does not work well in trailers do to the consent flexing of the floor assembly. The trailers main use should be the determining factor in flooring selection, as an example carpet would not work well in a mass causality or hazmat trailer.

Lastly the interior finish consists of three basic offerings. Aluminum which is the identical product used on the exterior, rough or finished plywood, or a easy clean lauan

Floors can be covered with a multitude of products

product similar to those used on home kitchens and bathrooms. Your dealer can help you match the interior sidewall finish to the application.

When ordering most trailer builders offer numerous interior options including lighting, wall coverings, floor coverings, cabinets, and tie-downs. Your trailer can be delivered with the interior finished to any level you wish. This can allow for cost savings by doing some of the customization in house.

Your roof can be used for more than protection from the elements. It can be prime storing area or even an observation deck

Roofing Materials
Roofing materials offered are of two basic types, aluminum and fiberglass. While the light penetrating capabilities of fiberglass roof system may look good on paper they do have issues which make them a bad choice. If heating or cooling the interior of your trailer is necessary fiberglass may hinder the process. Light passing through the material also transmits heat, a friend the cooler months, a foe in the summer months.

Fiberglass also seems to deteriorate when exposed to UV rays long term. Lastly damage to the fiberglass panels can actually spread when exposed to wind forces at highway speeds and is not easily repaired.

Roofs are offered in both flat and bowed configurations. Specify a flat roof, this gives you access to all the roof top features covered in this article.

Most manufactures offer a walk on roof option, this adds plywood to the roof system just under the top skin. A walk on roof does not necessarily include any type of alteration to the outer skin of the roof. If you want diamond plate or similar material you would have to have it added at an extra cost. I recommend the walk on roof option on all trailers over 14 feet in length. You just don't know what equipment may be needed in the future that would  require roof access. An additional plus is the stiffing of the roof and thus the whole body assembly.

Aluminum is the best choice; while not exotic it offers reasonable strength, helps with cooling by reflecting light and tends to isolate damage. Small holes are easily fixed with a patch/sealer system. Aluminum roofs are also more forgiving of dropped objects or equipment should a rooftop observation deck be included in your specifications. If possible request a one piece seamless roof to prevent unwanted leakage.

Hauling the Load
In emergency services usually once a trailer is set up it changes very little during its life time. This makes the initial planning and weight layout very important.

When loading your trailer, make sure enough weight is being carried on the hitch to ensure proper weight distribution and good handling. In some cases such as mobile command centers the trailer will not even come close to the maximum GVW. Keep this in mind during design and try to sufficiently load both the axle and hitch areas

Tow vehicles need not be limited to

SUVs or Pick-up trucks.

Do not exceed the capacity of your trailers running gear. Overloading can seriously degrade the life of the various components, result in unsafe braking and may lead to catastrophic failure It is very important to pull your trailer so that it is running level.

Support the back of the trailer at the ramps when loading up equipment or vehicles to prevent overloading the rear axle.

Other Options Worth Considering
More can be found at the Pa Firefighter Trailer Idea Gallery

		Roof top observation decks – The advantages and uses are obvious. There are a  few points to cover however. You must order you trailer with a walk on roof, this in most cases incorporates plywood decking into the roof structure.  Mount the access ladder inside the trailer to control roof access. There are several folding ladders on the market which will not take up any useable space with in work area. Complete the system by having your  builder pass the ladder through a standard vehicle escape hatch.
		Stabilizer Jacks – For larger trailers utilized in a command functions or similar stabilization is a must. Stabilizers both level and stiffen the trailer. Systems are available ranging from small, manually operated jacks to fully automated leveling systems requiring only a push of a button to level the whole rig.
		Utilities – Pre-wire utilities such as phones, networking cables, and electrical components. Even video camera and monitor cables are much easier the add during construction. Give each system a weather proof shore connection to accept outside resources. Don't forget the potential problems causes electrical induction, metal trailer bodies sometimes compound the problem. I still recommend the hardwiring of computer networks for security, check with you IT personnel on these issues.
		Mast System – Come in handy for raising antennas, lights, camera, or even satellite dishes. Mast units vary in size and complexity. Units on the basic side use a simple cable crank method to deploy, with more advanced units using air or even hydraulics to deploy.
		Interior Lights – Florescent fixtures work best for lighting the space but require some precautions to help control breakage when in transit. A few 12 volt ceiling lights come in handy when a quick task inside the trailer is needed. The 12 volt lights run off the tow vehicles electrical system via the trailer light plug and socket.
		Exterior Lights – Install both flood and ground level lighting also add exterior electrical outlets for additional area lighting around outside work stations or for lighting command boards etc.
		Roof Vents - Vents come in several styles mounting on both the roof and sidewalls. The standard 14"x14" roof vent can be replaced with a RV heating and air conditioning unit at a later date as they both use a 14"x14"roof opening.  Note: Some strengthen of the roof is necessary to support the AC unit. Have this done at the time of manufacture.
		Heating and Air Conditioning - Heating and Air conditioning units are available in a range of BTU ratings. These units utilize traditional compressor or modern heat pump technologies and are very efficient. This option is surprisingly easy to add to existing trailers as well. Hint: Heating is added via the ceiling assembly, an existing ac unit can have heat added by swapping out this unit a inexpensive and easy alteration.
		Cabinetry - Can be simple or complex. Basic good quality metal clad cabinets are available from just about every trailer manufacturer. This system while actual aimed at racing teams may be all you need. More complex, mission specific system such as the example pictured to the left can be done in house using component systems available at most lumberyards.
		Windows and Doors – Be sure you are clear on the door type when ordering. As an example, If you are constructing a mobile command unit you want RV doors not cargo doors. Also consider size, if  you're going to have hazmat techs utilizing the door in  level A full encapsulation suits the standard width door is not going to work
		Awnings – Both Sides - Awnings not only add areas of shade and protection from the weather but they also define areas of importance. Thanks to the general RV industry awnings are extremely durable and very easy to deploy.
		Generator sized to match - Mount the generator to the tongue of the trailer rather then having a generator compartment built in the trailer. Not only does it save valuable space inside the trailer but it also helps isolate the vibrations to the trailers frame rather then the body. This also provides the option of removing it from the trailer and relocating  it away from your work area to limit noise. Additionally have shorelines added to the trailer for an alternate power supply, again to get the noise and heat away from the trailer during extended operation.