Introduction

Requirements for masonry testing and the proper testing procedures are frequently misunderstood, often resulting in unnecessary sampling, inconsequential noncompliance reports related to low breaks, and misinterpretation of test results. In many cases, masonry sampling and testing are not performed in accordance with approved procedures. In this article EPIC hopes to clarify the building code requirements for masonry testing for designers, owners, and inspectors.

The Quality Assurance (QA) requirements of masonry construction are provided in section 1705.4 of the 2022 New York City Building Code (2022 NYC BC). The 2022 NYC BC reference TMS 402/602 Building Code Requirements and Specification for Masonry Structures (TMS 402/602).

As per TMS 402/602:

• Per TMS 402/602, the specified compressive strength of masonry, f’m, is the governing material property for both clay and concrete masonry. This value may be established using one of the following methods:

• The Unit Strength Method[BT1] : uses mortar and unit (block or brick) strength values to determine f’m using Tables 1 or 2 in TMS 602 1.4 B.2.

• The Prism Test Method: uses a small-scale assembly of the wall built in the field or saw cut from an already built wall.

• In case there is a reason to doubt the proper masonry construction (low breaks, missed inspections, etc.) these values are validated through The Prism Test Method.

From Reinforced Concrete Masonry Construction Inspector’s Handbook (Chrysler, 2010):

The scope of the quality assurance program should include verification of f’m by the Prism Test Method, the Unit Strength Method, or Testing Prisms from Constructed Masonry. Tests may also include units, mortar or grout, however these tests are unnecessary and redundant when testing masonry assemblages.  

Unit Strength Method

The Unit Strength method determines f’m by using results from the masonry unit strength and mortar type which are used to look up the corresponding f’m in the table corresponding to the unit type (clay or concrete masonry).

Unit

Often overlooked – the unit of the masonry element (CMU, Brick, terra-cotta etc.) has to be tested to determine the masonry strength - f’m using the table. Unit strength is performed per ASTM C140 for CMU and ASTM C67 for Brick and clay tile.

Mortar

Regarding the mortar testing, there are two mortar testing standards, ASTM C270 and ASTM C780. ASTM C270 is for mortars sampled and tested in the lab while ASTM C780 is for mortar sampled and tested in the field. ASTM C270 lists values for mortar strength for type M, S, N, and O mortars, however these values are not required to be met by compressive testing as per ASTM C780. In other words, mortar quality control is performed by verifying the mixing procedures, not compressive testing; low breaks are not basis for rejection as outlined in the testing standards.

Additionally, Per TMS, there is no compression testing requirement for veneer. “TMS 402 12.1.1.3 Articles 1.4 A and B and 3.4 C of TMS 602 shall not apply to any veneer.”

Grout

Although grout strength is not used to determine f’m, it is required to conduct a minimum compressive test:

TMS402/602: 2.2B When f'm exceeds 2,000 psi (13.79 MPa), provide grout compressive strength that equals or exceeds f'm. Determine compressive strength of grout in accordance with ASTM C1019.

Grout prisms are made using ASTM C1019: either by specialized cardboard forms or using the units on four sides and wetted paper towels. This is done to replicate the moisture absorption that is going to take place during grouting.

Sampling grout using plastic cylinders (ASTM C39) is not allowed.

The Prism Test Method

When validation of the compressive strength is desired, the Prism Test Method is conducted according to ASTM C1314. This requires physical testing of an assembly built on site or cut from an existing wall.

 Frequency of Testing

Frequency of testing is determined by the designer. Depending on Level B or Level C masonry special inspections that are established by the designer, the code outlines minimum testing. The designer may specify a higher amount of sampling and testing than the code requires.

In short:

• Level B applies for Risk Category I, II, or III buildings that are three stories or less, and requires f’m verification prior to construction.

• Level C applies for masonry in buildings greater than three stories, and for certain engineered masonry in Risk Category IV, and requires f’m verification prior to and every 5,000 sq. ft. of masonry construction.

Self-Consolidating Grout (SCG)

Where self-consolidating grout is used, the code requires verification of “slump flow and Visual Stability Index (VSI) as delivered to the site”, per TMS 602 Article 1.5.B.1.b.3 (Level B and Level C programs both reference this minimum test).

Non-potable water systems distribute water that is not designed for human consumption but are an efficient and environmentally friendly way to operate a wide range of appliances, including toilets and irrigation systems. However, it is imperative that this type of system is installed and inspected properly to avoid leaking, or worse, contamination of drinking water. As such, there are eight tests and visual inspections, specified in Sections 108, 312, and Sections 1302.12.1 through 1302.12.7 of the 2022 NYC Plumbing Code, that must be performed to ensure proper installation.

Collection pipe and vent:

Collection pipes and vents can be tested using water, air, or smoke, but must have no leaks and be tight at all points.

Storage tank:

Storage tanks must also be tested for leaks, but there are 3 specific parts of the storage tank that require close inspection. The overflow system must be verified to have no leaks and proper drainage, the tank drain must be observed for proper operation, and the makeup water system must be observed not only for proper operation but also for automatic shutoff of the system at the refill threshold.

Water supply system:

On top of all the previous leak tests, the entire system (or in some cases just the completed portion) must be pressure tested for leaks above its working pressure. This must be done using potable water.

Backflow prevention assemblies:

Errors or defects in backflow prevention assemblies pose some of the highest risk to public health, in that they can contaminate potable water systems. Because of this, all backflow prevention assemblies must be inspected and tested after installation or repairs and annually thereafter. This includes but is not limited to air gaps, spill-proof vacuum breakers, pressure vacuum breaker assemblies, and hose connection backflow preventers.

Vermin and insect protection:

As many non-potable water systems use air gaps and vents, proper measures must be taken to protect the system (and thus the buildings and people who use it) from insects and other vermin.

Water quality:

Though it is not necessary for every system, some non-potable water systems treat the water before it is used. When they do, the water quality must be tested and monitored to ensure safe use.

Cross connection control:

A lot of work goes into backflow prevention and inspection, but all of this becomes for nothing if the nonpotable water system is connected to a potable water system without the proper air gap. On top of this proper signage must be displayed to reduce the risk of future cross connections, and the pipes that carry non-potable water must be purple in color.

Roofwasher (if applicable):

Roofwashers must be tested by introducing water into the gutters to verify that enough rainwater is diverted in order to clear debris, that the amount of diverted water is field adjustable, and that diverted water is drained properly. On top of this, it must be verified that the roofwasher operates automatically and is accessible for maintenance and service.

Every system is unique and poses a unique set of challenges. No matter the type of non-potable water system, we at EPIC are always prepared to provide the diligent oversight and code-required inspections that these systems require.

EP Inspections & Commissioning hit a major milestone as the firm has officially expanded its Class 1 Accreditation from the International Accreditation Service (IAS) to cover all Special Inspections offered in New York City.

This achievement builds on EPIC’s initial Class 1 accreditation, obtained in May 2021 for a limited number of inspection types. Since then, the team has worked diligently through the rigorous annual renewal process and added 34 additional inspection categories—broadening their capabilities to include inspections for projects of any class and size, from small renovations to large-scale high-rise developments.

With this expansion, EPIC is now authorized to conduct critical inspections such as support of excavation, structural foundations, deep foundations, seismic resistance, and all types of mass timber construction, in addition to their existing specialties like mechanical systems, sprinkler and standpipe systems, and emergency power systems.

As a fully accredited Class 1 firm, EPIC continues to set the standard in the industry—known for their engineer-led approach, clear communication, and commitment to quality. This expanded scope reinforces EPIC’s role as a trusted partner on complex construction projects across New York City.

As large Mass Timber construction has become more of a reality in New York City in recent years, there has been a lot of code development for Mass Timber construction in NYC and International building codes, having both design and inspection implications. (See this DoB presentation regarding the most recent code changes regarding Mass Timber). To appropriately specify the correct inspection types when filing projects on DoB Now, it's important to distinguish between Engineered Wood Products and Conventional Wood Construction.

Engineered wood products, such as Cross Laminated Timber (CLT), Structural Composite Lumber (SCL) or Structural Glued-Laminated Timber (Glulam) are described are defined in the NYC Building code as follows:

• CROSS-LAMINATED TIMBER (CLT): A prefabricated engineered wood product made of at least three orthogonal layers of graded sawn lumber or structural composite lumber (SCL) that are laminated by gluing with structural adhesives.

• STRUCTURAL COMPOSITE LUMBER: Structural member manufactured using wood elements bonded together with exterior adhesives.

• STRUCTURAL GLUED-LAMINATED TIMBER: An engineered, stress-rated product of a timber laminating plant, comprised of assemblies of specially selected and prepared wood laminations in which the grain of all laminations is approximately parallel longitudinally and the laminations are bonded with adhesives.

The products listed above come with sets of rules for attachment, notching, bearing, connector installation, erection, etc., that are usually listed by the manufacturer.

Engineered wood products can fall under the full list of Wood Construction Inspections per NYC Building code, found in section 1705.5, depending on the EoR specifications. These inspection types are:

1. 1705.5.1 High-Load Diaphragms

2. 1705.5.2 Metal-Plate-Connected Wood Trusses

3. 1705.5.3 Prefabricated Wood I-Joists and/or Glued Prefabricated Parallel Chord Wood Trusses

4. 1705.5.4 Other Structural Wood Construction 

5. 1705.5.5 Special Inspection for Seismic Resistance

6. 1705.5.6 Type IV Construction

Conventional light framed wood construction inspections fall under the progress inspection 1705.5.4 Other Structural Wood Construction:

All other structural wood construction shall be subject to progress inspections for the structural frame to the extent required by Section 110.3.3.

110.3.3 Structural Wood Frame Inspection (in the Administrative chapter of the Building Code) states:

Inspections shall be performed for wood structural framing to determine compliance with the approved construction documents.

The reality is that with New York City's overwhelming existing building stock of townhouses, rowhouses, tenements and 1-2 family detached houses, the bulk of construction and inspection work in terms of wood construction comes down the conventional wood construction. Types of buildings listed above rely on wood framed floors, diaphragms, and sometimes wood framed bearing walls. Any time the framing is altered, the load path needs to be re-established, framing and sheathing designed and inspected as per code.

EPIC provides a comprehensive inspection program for wood construction, whether it be type IV construction, light framed wood construction, high load diaphragms, or any other wood construction type. With our qualified staff and detailed inspection checklists we deliver high quality oversight of the wood construction to ensure adherence with construction documents and all code requirements.