Maintenance control programs

Hugh Mbeki came to the Northcrest shop on Tamsin's second Monday with a box of binders and a laptop. He was the company's maintenance quality manager, a former route mechanic who now spent his time auditing routes, training mechanics on the paperwork and answering for the company when an authority asked hard questions. “Every unit you touch has a maintenance control program,” he told her. “It is the contractor's written promise of what will be done to that elevator, how often, by what procedure, and where the proof is kept. If the work is not in the program, the inspector will say it is not being done. If it is in the program and not in the records, the inspector will say the same thing.” He gave her the binder for Larchmont Residences and asked her to read it end to end before her next visit there. This lesson covers what a maintenance control program is, what the code requires it to contain, and how its records are kept.

What the code requires

Section 8.6 requires a written maintenance control program for each unit, specific to that unit, which is kept on site or is otherwise available to the mechanics and the authority. The program sets out the examinations, maintenance and tests to be done and the intervals at which they are done. The intervals are not chosen freely. They must take account of the maker's procedures and recommendations, the age, condition and accumulated wear of the equipment, its design and the quality of its parts, the usage, the environment it works in, and the results of past maintenance and tests. A car that runs four hundred trips a day in a hospital needs a different program from the same model in a quiet apartment building, and a program that ignores the difference does not meet the code. The program must also include the procedures for the periodic tests required by Part 8, and for any tests the maker or the code requires for particular devices.

Several kinds of procedure must be in the program or available on site because a mechanic cannot work safely without them. They include the maker's procedures for testing and adjusting devices that use software or electronic safety systems, procedures for checking out the equipment and returning it to service after work, procedures for unique or product-specific tests, procedures to follow after a loss of traction or a safety application, and procedures for evacuating passengers. Up-to-date wiring diagrams must also be kept on site, because a mechanic tracing a fault on a controller cannot rely on memory or a diagram for a different job number.

The task list

The heart of the program is the task list. Each task names a component or device, what is to be done to it, the procedure or reference, and the interval. A typical traction elevator program has between a hundred and two hundred tasks: examine the brake and measure its lining, lubricate the rails if they are oiled, clean and examine the car door sill and tracks, check the door closing force and time, examine the governor and its rope, examine the suspension means and record its condition, test the car emergency light and the emergency communication, and so on through the machine, the control space, the hoistway, the car and the landings. Many contractors organize the list by location, so that a mechanic working through the machine room does all the machine room tasks due that month before moving to the car top, which saves time and keeps people out of the hoistway as much as possible.

Tamsin noticed that several of Larchmont's intervals were shorter than the maker's recommendation. Hugh explained why: the program had been reviewed after the car's first winter, when a belt monitor trip in cold weather (from ELV-230) and a cracked hall door gib (from ELV-320) showed that the building's heavy furniture traffic and cold lobby were harder on the car than the maker had assumed. The program is a living document. When usage changes, when findings show unexpected wear, or when equipment is replaced or altered, the intervals and tasks must be reviewed and changed, and the change recorded.

Scheduling the tasks

Each task's interval and the month it was last done decide when it is next due, and each month's visit is built from the tasks that fall due. Most contractors now do this with software, but the logic is simple enough to write out, and Hugh asked Tamsin to do it for Larchmont so that she would understand what the software was doing. Some tasks also carry a usage factor: on a heavily used car, door and brake tasks come round more often.

# Build a 12-month schedule from a task list: (task, interval in months, month last done, heavy-use task?)
tasks = [
    ("machine and brake examination", 1, 12, False),
    ("belt monitor status check",     1, 12, False),
    ("door sills and tracks",         1, 12, True),
    ("door force and time",           6, 9,  True),
    ("belts and terminations",        6, 10, False),
    ("governor and governor rope",    3, 11, False),
    ("pit and buffers",               3, 10, False),
    ("emergency light and phone",     1, 12, False),
    ("Category 1 tests",             12, 4,  False),
]
HEAVY_USE = True     # Larchmont: heavy furniture traffic, so heavy-use tasks run at half interval (at least 1 month)
months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]

def due_months(interval, last, heavy):
    if heavy and HEAVY_USE:
        interval = max(1, interval // 2)
    m, out = last, []
    while True:
        m += interval
        if m > 24:
            return out
        if 13 <= m <= 24:
            out.append(m - 12)

plan = {m: [] for m in range(1, 13)}
for name, interval, last, heavy in tasks:
    for m in due_months(interval, last, heavy):
        plan[m].append(name)
for m in (1, 3, 4, 6):
    print(f"{months[m - 1]}: {len(plan[m])} tasks -> " + "; ".join(plan[m]))
print("task count per month:", [len(plan[m]) for m in range(1, 13)])

Jan: 5 tasks -> machine and brake examination; belt monitor status check; door sills and tracks; pit and buffers; emergency light and phone
Mar: 5 tasks -> machine and brake examination; belt monitor status check; door sills and tracks; door force and time; emergency light and phone
Apr: 7 tasks -> machine and brake examination; belt monitor status check; door sills and tracks; belts and terminations; pit and buffers; emergency light and phone; Category 1 tests
Jun: 5 tasks -> machine and brake examination; belt monitor status check; door sills and tracks; door force and time; emergency light and phone
task count per month: [5, 5, 5, 7, 5, 5, 5, 5, 5, 6, 5, 5]

The schedule shows the uneven months that a mechanic plans around. April carries the Category 1 tests as well as the regular tasks, so Ray booked a longer visit and a second person that month. Spreading the six-month and three-month tasks so they do not all land together is part of writing a good program; a schedule that puts every big job in one month will be done badly or late.

The records

A program without records proves nothing. Section 8.6 requires records of the maintenance done, of repairs and replacements, of callbacks or trouble calls with their causes and corrective action, of oil usage on hydraulic elevators, and of the periodic tests with their results. The records must show who did the work and when, and they must be available to the authority. The test records must include the actual values measured, not just a tick: a governor test record with no tripping speed, or a relief valve test with no pressure, is not a test record.

In Washington, L&I's maintenance control program forms give the structure most contractors follow. The on-site binder holds the program documents permanently: the task procedures, as-built wiring diagrams, procedures for electronic safety devices, checkout and evacuation procedures, and any alternative arrangements. Unit records are kept on site for five years: maintenance records, code non-compliance records, repair and replacement records, suspension replacement criteria, test records and the callback log. Monthly logs list tasks by location with their intervals and due months, completed with the mechanic's initials, and Category 1 and Category 5 tests are recorded on the state's test form. In Seattle, the SDCI inspector checks these records at the annual inspection.

Reading a program as an inspector does

Hugh gave Tamsin the four questions he asks of every program, because they are the questions the authority will ask. Is it specific to this unit, or a generic list copied from another job? Are the intervals justified by the maker, the usage and the history, and have they been reviewed when those changed? Do the records show every task done at its interval, with the tests carrying real values? And do the equipment and the records agree, or does the clean log sit beside a dirty pit and a brake worn past its limit? Tamsin read the Larchmont binder with those questions and found two things to raise: the belt examination task referred to the maker's procedure by a revision number that the maker had since replaced, and the oil usage page for the hydraulic buffer was blank because nobody had thought of the buffer as a place where oil is used. Hugh was pleased with both. The first was a document control problem; the second turned out to matter in lesson 8.