P.O. Box 10264 Burbank, California 91510
This article started out as a story about a Case steam tractor but turned into an essay on what we here in Southern California have to do to get a tractor boiler certified. The Case steam tractor is located at the Early Day Gas Engine and Tractor Museum in Vista, California.
Let me start at the beginning.
We at the museum in Vista have had a Case 60 HP steamer for a long time, but it has not been run in seven or eight years. She was over-fired for a few years and left with her nose dirty. When last put up, the boiler was full of water and the flues were leaking. The end result has been that the ash and water combined, and over the last number of years the rivets in the nose have been rusting away.
About five years ago, I got involved with steam tractors here in Vista. At that time none were running but we now have an Advance and a Russell operating at our shows and we are working on the Case. Here in Southern California, as in other places, we are required to have our boilers certified by the state. Here however, the difference is that it will usually take a year or so to certify each tractor! This is, in part, because our insurance inspector and our state inspector had not ever seen a steam tractor before. When we asked what was needed to get certification it took not less than six months to get a two-page letter from the state capital listing the requirements for certification. Here are some of the requirements they asked for:
1. A complete set of drawings including vessel joint details and any internal and external attachments.
2. A list of all known original or existing design criteria, maximum allowable working pressure and temperature, heat treatment, corrosion allowance, impact test, lethal service, loadings, direct firing, service restrictions, etc.
3. If the design was not based on code rules, we are to provide a copy of the source of design rules used.
4. Evidence of any existing original mill identification on vessel materials. If such data is not available, provide documentation on tests made in accordance with material specifications designated for the applicable code section, as follows: Chemical Analysis, Tensile Tests, Hardness, Bend Tests. In addition show a comparison to code material and indicate how they are equivalent.
5. Reports on tensile and bed tests on head and shell.
6. Reports on liquid penetrate tests of all corner joints.
Collecting enough original literature or copies thereof to show the factory specified thickness of the sheets and rivets, as well as the tensile strength and chemical composition of the metal, is a job to say the least. The drawing of the boiler had to be made and together with several pages of calculations, all stamped by a certified professional engineer, then go to the state for approvals, then and only then will they come out to see the boiler itself. With time and money, much of this can be done, but there are some things that the original literature will not tell you, like the amount of phosphor and sulfur in the boiler plate. The usual way of getting this information is to cut sample test plates from the boiler and send them out to a lab. This will mean that you will have two or three holes, 1' by 9' or so, in your boiler that will have to be patched up, and in California that will require an expensive California certified boiler welder! Luckily, we have been spared that part so far, mostly because of the fact that our tractors are all large brand name tractor companies. Research has shown that there was an ASME origination back in the late 1800s. They were not the organization they are today but they did publish papers on how to design a good boiler. There were no laws at that time that said you had to do it their way, but the insurance companies were requiring the manufacturers to go by the ASME (and other) guidelines or they would not insure the company's product.
In a roundabout way, the major companies all used the same guidelines for boiler construction. Many of the definitions and calculations that the ASME uses for the type of boiler on steam tractors have not changed since the late 1800s or early 1900s. The definition of fire box steel or flange steel and the calculations for stay bolt spacing etc., are virtually unchanged. Based on this the state has agreed to let us pass on these rather destructive tests to our boiler shells. One thing that is harder for us here, than it is elsewhere, is that we must have a safety factor of eight on our tractor boilers. That is to say that the boiler must have been designed to withstand eight times the operating pressure and not explode! A lap seem boiler here in California is limited to 100 p.s.i., so the boiler calculations must show that the boiler would hold at least 800 p.s.i. when it was new.
By comparison, a new boiler today is usually built to a safety factor between four or five. However, each state has its own set of rules. Also, if there are any paid employees at the museum, OSHA will get involved.
There is more I could say, but enough for now. Let me get back to our 60 horse Case. The first chore we have to do is to replace some eight or nine rivets in the nose. A local boiler company has quoted us $3000 for that job! We also need to replace the flues; the same company quoted us $5000 for that. These prices are way out of line for a museum like ours. Like most of you, we are a non-profit organization. We have found a boiler company sympathetic to our cause, and if we do most of the work (which we like to do anyway), they will finish and take responsibility for the job. This will make the state happy because there is a qualified boiler company involved and it makes us happy because it will not cost us nearly so much money.
So things are now in place for us to begin returning the Case back to operational status and it will now take only time and a bit less money.
Photo courtesy of Tim Sollman, 897 - 2 3/8 St., Clayton , WI 54004. Location unknown any one have any ideas?
Along this line, we thought we would make available the detailed drawing of the boiler for our tractor. It is a highly detailed drawing of the boiler, inside and out, approximately 24' by 18', and shows virtually every rivet and stay bolt along with dimensions, etc. It is a slightly modified version of the one approved by the state for our certification. An ad for the drawings appeared on page 36 of the July/August IMA with the details. All profits will go directly to the restoration of our Case steamer.
We hope to show off this engine again soon and then you will probably see a picture of it here.