The first rule of fireplace safety is to keep your fireplace clean. Regular inspections can be done by the homeowner, but a professional inspection should be scheduled every two or three years depending on how regularly it is inspected by the homeowner. Without periodic inspections, creosote, a flammable byproduct of wood, can build up in the flue and ignite.
Also, make sure any flammable material, including decorations and debris, are a safe distance from the chimney box. This is especially a concern when the hearth is the centerpiece of a room. People tend to over-decorate the hearth with, for instance, stockings or fabric overhangs, which can catch flame if they are not kept at a safe distance.
Finally, make sure you are safely burning your fuel. Do not use flammable liquids to start your fire. Never burn cardboard or other trash in your fireplace. You do not know what these materials are made of and they can burn in unexpected and dangerous ways.
There are some general rules concerning the building of fireplaces that you can consider before building.
First, know that the outside of the chimney needs to be at least four inches larger around than the flue inside. This will help when determining how well the fireplace will fit in your room.
Second, if you are building an exterior chimney, the chimney must be at least three feet above the roof, and one foot from a combustible wall.
Also, exterior chimneys must be anchored every eighteen inches, so have space to do this or the chimney will be structurally unsound.
There are many other things to consider, such as your local climate. This does not mean simply considering whether it is typically hot or cold where you live, but any weather extremes your chimney would have to endure, such as a blizzard, tornado, or earthquake. It is for this reason it is recommended that, once you decide to build, you consult a professional.
It is important to note two things before continuing. First, codes and regulations for fireplaces vary by state and type of fireplace and chimney, so consult with a state approved official before beginning a build. Second, the following self-inspection of a chimney should not be interpreted as a way around paying professionals. However, much like fixing your car or patching a hole in your wall, there are certain projects which can easily be achieved by the do-it-yourself homeowner. A basic inspection is one of those projects, and it is an excellent way to catch early any issues which may require a professional.
You can remove the ashes from the chimney box most effectively by utilizing a few methods. A simple broom and dust pan can take care of the loose ash. You can clean further through the use of a chimney brush and still further with a vacuum. To avoid clogging the vacuum, make sure what you intend to vacuum is fine.
With the chimney box cleaned as much as possible, lie something you do not mind getting dirty on the floor so you can slide on your back into the box. Have a flashlight to shine up into the flue. Check for cracks and the condition of the damper.
While still lying on the ground, have someone operate the damper and watch it to see that it is operating properly. You will want to wear protective eyewear for this task.
Once you have reached your chimney, shine your flashlight down into the flue, checking for creosote, a flammable brown or black substance which can build up and ignite without proper chimney maintenance. Using a stiff brush, remove as much creosote as possible.
It is important to remember that the safety codes for the building and maintenance of a fireplace change from state to state. These changes can be extremely important, as the codes in, for instance, Arizona, with its hot, dry climate will be different from the codes for Washington state. Codes reflect the best practices for a certain climate and should not be considered universal.
Finding the codes and regulations for your state should be easy. Simply by searching online, the codes should be available.