Tank cleaning | safety / schedule / cost
Tank cleaning is a periodic task that cannot be avoided.
Sludge build-up, a change of stored product, tank inspection and maintenance, internal examination — any of these can create a cleaning requirement. In the past, cleaning relied heavily on personnel entering the tank to clean it by hand. As safety management requirements have risen, the cost of organising manual work has increased and mechanised equipment has matured, traditional manual tank cleaning now faces pressure on safety, schedule and total cost.
This does not mean manual cleaning has been phased out entirely. It means that when a company plans a cleaning job, it needs to rethink two questions:
Which work genuinely requires people to enter the tank?
Which work can be handed to equipment?
01 Safety pressure: entry into a tank is itself a concentration of risk
The defining feature of traditional manual tank cleaning is that a large part of the work has to be carried out by people inside the tank.
The interior of a tank often combines several hazards at once: a confined space, flammable and explosive atmospheres, toxic and harmful gases, oxygen deficiency and static electricity.
A manual entry job is therefore not simply "go in and shovel the sludge out". It requires all of the following to be managed:
- tank isolation and preparatory treatment;
- ventilation and gas testing;
- explosion protection and static control;
- personal protection;
- on-site attendance and supervision;
- emergency rescue readiness.
A failure at any one of these points can directly affect the safety of the people inside the tank.
AQ 3042-2025, Safety specification for tank cleaning operations in onshore oil and gas fields, took effect on 1 July 2026 and sets systematic safety requirements covering site survey, work plan, gas testing, manual cleaning and mechanical cleaning. It is a mandatory work safety industry standard and replaces AQ/T 3042-2013.
For companies, this means tank cleaning cannot be judged solely by whether the tank ends up clean. Whether the working method itself reduces risk to personnel matters more and more.
02 Schedule pressure: more people does not necessarily mean faster cleaning
Cleaning a large tank normally runs through taking the tank out of service, draining the oil, handling residual oil, ventilation, testing, removing sludge and a final inspection.
Traditional manual cleaning depends heavily on how personnel are organised on site and on the working conditions inside the tank.
Any of the following:
- gas testing that does not meet entry conditions;
- high temperature or other unsuitable working environments;
- rotation of the work crew;
- sludge thickness or viscosity beyond expectations;
- a need to stop and re-ventilate and re-test on site;
can directly affect cleaning progress.
By comparison, mechanised cleaning can carry out more of the early cleaning work continuously through circulation, suction and jetting equipment, moving part of the work that used to be done by people inside the tank to the equipment side.
A 2025 study of a mechanical cleaning project on large floating-roof crude oil tanks, published in Petroleum Engineering Construction, reports that in the project concerned the cleaning cycle per tank was shortened by 20 days after the corresponding mechanical cleaning method was adopted.
At the very least this shows one thing:
for projects where mechanised working is feasible, reducing reliance on long periods of manual entry can create more room for construction planning and schedule control.
03 Cost pressure: it is not only about "how much the workers cost"
When cleaning cost comes up, labour cost is the first thing that springs to mind.
What a company actually needs to calculate, however, is the total project cost.
Besides the site workforce, that may include:
- the operational impact of the tank being out of service;
- spend on ventilation, testing and protection;
- rotation of personnel inside the tank and on-site supervision;
- cleaning equipment and ancillary facilities;
- treatment of residual oil, sludge and waste liquid;
- project management and safety assurance.
If the cleaning cycle is long and the tank cannot be returned to service promptly, time itself becomes a cost.
The benefit analysis in the Petroleum Engineering Construction study cited above, for a specific large tank project, shows that compared with traditional manual cleaning, its mechanical cleaning method reduced labour cost by 46.99% and total cost by 27.59%. This points to a way of thinking worth noting:
a cleaning proposal should not be judged by comparing equipment rental against unit labour rates alone; schedule, personnel input and project organisation should be included in the calculation.
04 Mechanised cleaning is not simply about "using a few less people"
Mechanised tank cleaning is not a matter of swapping one tool in a manual cleaning job for a machine.
The current standard SY/T 6696-2025, Code of practice for mechanical cleaning of oil storage tanks, took effect on 18 June 2026, which shows that mechanical cleaning of oil storage tanks now has its own dedicated industry procedure; tank cleaning equipment is also covered by industry standards such as JB/T 13138-2017.
In practice, mechanised cleaning can combine suction, circulation, flushing and recovery so that more of the work is completed before anyone enters the tank.
The change it brings shows up mainly in three ways:
First, it reduces the need for people to enter the tank directly.
Work that equipment can do is carried out outside the tank wherever possible, reducing both the time and the occasions on which people are directly exposed to a high-risk environment.
Second, it makes the cleaning process more continuous.
Mechanical equipment can run circulation, suction and flushing to a set procedure, reducing the effect that some manual work inside the tank has on the pace of the job.
Third, it supports a more complete cleaning workflow.
Some mechanised solutions can link cleaning, residual oil recovery and subsequent treatment, rather than simply completing the step of "getting the sludge out".
Mechanisation does not mean there is no safety risk, and it does not replace gas testing, on-site supervision, explosion protection or other safety management requirements.
What it genuinely changes is this:
risk control moves further towards the front end, towards "fewer people entering the tank".
05 Why does equipment rental suit some cleaning projects better?
For tank operators there is another practical question:
should the company buy a complete set of equipment for a periodic cleaning requirement?
Mechanised cleaning equipment is highly specialised, yet tank cleaning tends to be periodic and project-based.
If a company cleans tanks only occasionally, buying its own equipment also means considering:
- where the equipment will be stored long term;
- whether it will sit idle between projects;
- who is responsible for routine maintenance and repair;
- whether the equipment will still suit the next tank and site conditions.
For companies without a long-term, high-frequency requirement, equipment rental can therefore be a more flexible arrangement.
Equipment is selected according to the specific tank and project requirement and used for the actual cleaning project; once the project is finished, the company does not need to hold the whole system long term, which reduces one-off equipment spend and the burden of ownership afterwards.
What a company really needs may not be "to own a set of cleaning equipment", but:
to be able to obtain a cleaning solution suited to the current project whenever a tank has to be cleaned.
Tecway Industrial | tank cleaning equipment rental and cleaning services
For companies with periodic tank inspection, maintenance and cleaning requirements, Tecway Industrial can provide rental of mechanised tank cleaning equipment together with supporting cleaning services, with the cleaning arrangement configured flexibly according to tank type, project duration and site requirements.
For companies that do not need to own a complete cleaning system long term, the rental model reduces one-off equipment spend. At the same time, mechanised cleaning reduces the need for personnel to enter tanks for high-risk work, improving working efficiency while taking better account of safety management and project delivery requirements.
References
- Ministry of Emergency Management: AQ 3042-2025, Safety specification for tank cleaning operations in onshore oil and gas fields
- National Energy Administration / National Public Service Platform for Standards Information: SY/T 6696-2025, Code of practice for mechanical cleaning of oil storage tanks
- National Public Service Platform for Standards Information: JB/T 13138-2017, Oil storage tank cleaning equipment
- Petroleum Engineering Construction: "Research and application of a mechanical cleaning construction method for large floating-roof crude oil tanks", 2025
About Tecway Industrial
Tecway Industrial System Limited, formerly Tecway International (Petrochemical) Limited, was founded in Hong Kong in 1995; Beijing Tecway Xuyang Industrial Equipment Co., Ltd. is its subsidiary registered in Beijing.
Tecway Industrial System Limited and Beijing Tecway Xuyang Industrial Equipment Co., Ltd. are mainly engaged in services related to the import of equipment for the oil and gas storage and transport and petrochemical industries. As consultants and distributors, we carefully select and provide our customers with feasible, high-quality and cost-effective solutions, sourced from reputable suppliers worldwide.